1 /*
   2  * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "aot/aotLoader.hpp"
  27 #include "classfile/classFileParser.hpp"
  28 #include "classfile/classFileStream.hpp"
  29 #include "classfile/classLoader.hpp"
  30 #include "classfile/javaClasses.hpp"
  31 #include "classfile/moduleEntry.hpp"
  32 #include "classfile/systemDictionary.hpp"
  33 #include "classfile/systemDictionaryShared.hpp"
  34 #include "classfile/verifier.hpp"
  35 #include "classfile/vmSymbols.hpp"
  36 #include "code/dependencyContext.hpp"
  37 #include "compiler/compileBroker.hpp"
  38 #include "gc/shared/collectedHeap.inline.hpp"
  39 #include "gc/shared/specialized_oop_closures.hpp"
  40 #include "interpreter/oopMapCache.hpp"
  41 #include "interpreter/rewriter.hpp"
  42 #include "jvmtifiles/jvmti.h"
  43 #include "logging/log.hpp"
  44 #include "memory/heapInspection.hpp"
  45 #include "memory/iterator.inline.hpp"
  46 #include "memory/metadataFactory.hpp"
  47 #include "memory/metaspaceShared.hpp"
  48 #include "memory/oopFactory.hpp"
  49 #include "memory/resourceArea.hpp"
  50 #include "oops/fieldStreams.hpp"
  51 #include "oops/instanceClassLoaderKlass.hpp"
  52 #include "oops/instanceKlass.inline.hpp"
  53 #include "oops/instanceMirrorKlass.hpp"
  54 #include "oops/instanceOop.hpp"
  55 #include "oops/klass.inline.hpp"
  56 #include "oops/method.hpp"
  57 #include "oops/oop.inline.hpp"
  58 #include "oops/symbol.hpp"
  59 #include "prims/jvmtiExport.hpp"
  60 #include "prims/jvmtiRedefineClasses.hpp"
  61 #include "prims/jvmtiThreadState.hpp"
  62 #include "prims/methodComparator.hpp"
  63 #include "runtime/atomic.hpp"
  64 #include "runtime/fieldDescriptor.hpp"
  65 #include "runtime/handles.inline.hpp"
  66 #include "runtime/javaCalls.hpp"
  67 #include "runtime/mutexLocker.hpp"
  68 #include "runtime/orderAccess.inline.hpp"
  69 #include "runtime/thread.inline.hpp"
  70 #include "services/classLoadingService.hpp"
  71 #include "services/threadService.hpp"
  72 #include "utilities/dtrace.hpp"
  73 #include "utilities/macros.hpp"
  74 #include "utilities/stringUtils.hpp"
  75 #include "logging/log.hpp"
  76 #ifdef COMPILER1
  77 #include "c1/c1_Compiler.hpp"
  78 #endif
  79 
  80 #ifdef DTRACE_ENABLED
  81 
  82 
  83 #define HOTSPOT_CLASS_INITIALIZATION_required HOTSPOT_CLASS_INITIALIZATION_REQUIRED
  84 #define HOTSPOT_CLASS_INITIALIZATION_recursive HOTSPOT_CLASS_INITIALIZATION_RECURSIVE
  85 #define HOTSPOT_CLASS_INITIALIZATION_concurrent HOTSPOT_CLASS_INITIALIZATION_CONCURRENT
  86 #define HOTSPOT_CLASS_INITIALIZATION_erroneous HOTSPOT_CLASS_INITIALIZATION_ERRONEOUS
  87 #define HOTSPOT_CLASS_INITIALIZATION_super__failed HOTSPOT_CLASS_INITIALIZATION_SUPER_FAILED
  88 #define HOTSPOT_CLASS_INITIALIZATION_clinit HOTSPOT_CLASS_INITIALIZATION_CLINIT
  89 #define HOTSPOT_CLASS_INITIALIZATION_error HOTSPOT_CLASS_INITIALIZATION_ERROR
  90 #define HOTSPOT_CLASS_INITIALIZATION_end HOTSPOT_CLASS_INITIALIZATION_END
  91 #define DTRACE_CLASSINIT_PROBE(type, thread_type)                \
  92   {                                                              \
  93     char* data = NULL;                                           \
  94     int len = 0;                                                 \
  95     Symbol* clss_name = name();                                  \
  96     if (clss_name != NULL) {                                     \
  97       data = (char*)clss_name->bytes();                          \
  98       len = clss_name->utf8_length();                            \
  99     }                                                            \
 100     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 101       data, len, class_loader(), thread_type);                   \
 102   }
 103 
 104 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)     \
 105   {                                                              \
 106     char* data = NULL;                                           \
 107     int len = 0;                                                 \
 108     Symbol* clss_name = name();                                  \
 109     if (clss_name != NULL) {                                     \
 110       data = (char*)clss_name->bytes();                          \
 111       len = clss_name->utf8_length();                            \
 112     }                                                            \
 113     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 114       data, len, class_loader(), thread_type, wait);             \
 115   }
 116 
 117 #else //  ndef DTRACE_ENABLED
 118 
 119 #define DTRACE_CLASSINIT_PROBE(type, thread_type)
 120 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)
 121 
 122 #endif //  ndef DTRACE_ENABLED
 123 
 124 volatile int InstanceKlass::_total_instanceKlass_count = 0;
 125 
 126 static inline bool is_class_loader(const Symbol* class_name,
 127                                    const ClassFileParser& parser) {
 128   assert(class_name != NULL, "invariant");
 129 
 130   if (class_name == vmSymbols::java_lang_ClassLoader()) {
 131     return true;
 132   }
 133 
 134   if (SystemDictionary::ClassLoader_klass_loaded()) {
 135     const Klass* const super_klass = parser.super_klass();
 136     if (super_klass != NULL) {
 137       if (super_klass->is_subtype_of(SystemDictionary::ClassLoader_klass())) {
 138         return true;
 139       }
 140     }
 141   }
 142   return false;
 143 }
 144 
 145 InstanceKlass* InstanceKlass::allocate_instance_klass(const ClassFileParser& parser, TRAPS) {
 146   const int size = InstanceKlass::size(parser.vtable_size(),
 147                                        parser.itable_size(),
 148                                        nonstatic_oop_map_size(parser.total_oop_map_count()),
 149                                        parser.is_interface(),
 150                                        parser.is_anonymous(),
 151                                        should_store_fingerprint());
 152 
 153   const Symbol* const class_name = parser.class_name();
 154   assert(class_name != NULL, "invariant");
 155   ClassLoaderData* loader_data = parser.loader_data();
 156   assert(loader_data != NULL, "invariant");
 157 
 158   InstanceKlass* ik;
 159 
 160   // Allocation
 161   if (REF_NONE == parser.reference_type()) {
 162     if (class_name == vmSymbols::java_lang_Class()) {
 163       // mirror
 164       ik = new (loader_data, size, THREAD) InstanceMirrorKlass(parser);
 165     }
 166     else if (is_class_loader(class_name, parser)) {
 167       // class loader
 168       ik = new (loader_data, size, THREAD) InstanceClassLoaderKlass(parser);
 169     }
 170     else {
 171       // normal
 172       ik = new (loader_data, size, THREAD) InstanceKlass(parser, InstanceKlass::_misc_kind_other);
 173     }
 174   }
 175   else {
 176     // reference
 177     ik = new (loader_data, size, THREAD) InstanceRefKlass(parser);
 178   }
 179 
 180   // Check for pending exception before adding to the loader data and incrementing
 181   // class count.  Can get OOM here.
 182   if (HAS_PENDING_EXCEPTION) {
 183     return NULL;
 184   }
 185 
 186   assert(ik != NULL, "invariant");
 187 
 188   const bool publicize = !parser.is_internal();
 189 
 190   // Add all classes to our internal class loader list here,
 191   // including classes in the bootstrap (NULL) class loader.
 192   loader_data->add_class(ik, publicize);
 193   Atomic::inc(&_total_instanceKlass_count);
 194 
 195   return ik;
 196 }
 197 
 198 
 199 // copy method ordering from resource area to Metaspace
 200 void InstanceKlass::copy_method_ordering(const intArray* m, TRAPS) {
 201   if (m != NULL) {
 202     // allocate a new array and copy contents (memcpy?)
 203     _method_ordering = MetadataFactory::new_array<int>(class_loader_data(), m->length(), CHECK);
 204     for (int i = 0; i < m->length(); i++) {
 205       _method_ordering->at_put(i, m->at(i));
 206     }
 207   } else {
 208     _method_ordering = Universe::the_empty_int_array();
 209   }
 210 }
 211 
 212 // create a new array of vtable_indices for default methods
 213 Array<int>* InstanceKlass::create_new_default_vtable_indices(int len, TRAPS) {
 214   Array<int>* vtable_indices = MetadataFactory::new_array<int>(class_loader_data(), len, CHECK_NULL);
 215   assert(default_vtable_indices() == NULL, "only create once");
 216   set_default_vtable_indices(vtable_indices);
 217   return vtable_indices;
 218 }
 219 
 220 InstanceKlass::InstanceKlass(const ClassFileParser& parser, unsigned kind) :
 221   _static_field_size(parser.static_field_size()),
 222   _nonstatic_oop_map_size(nonstatic_oop_map_size(parser.total_oop_map_count())),
 223   _itable_len(parser.itable_size()),
 224   _reference_type(parser.reference_type()) {
 225     set_vtable_length(parser.vtable_size());
 226     set_kind(kind);
 227     set_access_flags(parser.access_flags());
 228     set_is_anonymous(parser.is_anonymous());
 229     set_layout_helper(Klass::instance_layout_helper(parser.layout_size(),
 230                                                     false));
 231 
 232     assert(NULL == _methods, "underlying memory not zeroed?");
 233     assert(is_instance_klass(), "is layout incorrect?");
 234     assert(size_helper() == parser.layout_size(), "incorrect size_helper?");
 235 }
 236 
 237 void InstanceKlass::deallocate_methods(ClassLoaderData* loader_data,
 238                                        Array<Method*>* methods) {
 239   if (methods != NULL && methods != Universe::the_empty_method_array() &&
 240       !methods->is_shared()) {
 241     for (int i = 0; i < methods->length(); i++) {
 242       Method* method = methods->at(i);
 243       if (method == NULL) continue;  // maybe null if error processing
 244       // Only want to delete methods that are not executing for RedefineClasses.
 245       // The previous version will point to them so they're not totally dangling
 246       assert (!method->on_stack(), "shouldn't be called with methods on stack");
 247       MetadataFactory::free_metadata(loader_data, method);
 248     }
 249     MetadataFactory::free_array<Method*>(loader_data, methods);
 250   }
 251 }
 252 
 253 void InstanceKlass::deallocate_interfaces(ClassLoaderData* loader_data,
 254                                           const Klass* super_klass,
 255                                           Array<Klass*>* local_interfaces,
 256                                           Array<Klass*>* transitive_interfaces) {
 257   // Only deallocate transitive interfaces if not empty, same as super class
 258   // or same as local interfaces.  See code in parseClassFile.
 259   Array<Klass*>* ti = transitive_interfaces;
 260   if (ti != Universe::the_empty_klass_array() && ti != local_interfaces) {
 261     // check that the interfaces don't come from super class
 262     Array<Klass*>* sti = (super_klass == NULL) ? NULL :
 263                     InstanceKlass::cast(super_klass)->transitive_interfaces();
 264     if (ti != sti && ti != NULL && !ti->is_shared()) {
 265       MetadataFactory::free_array<Klass*>(loader_data, ti);
 266     }
 267   }
 268 
 269   // local interfaces can be empty
 270   if (local_interfaces != Universe::the_empty_klass_array() &&
 271       local_interfaces != NULL && !local_interfaces->is_shared()) {
 272     MetadataFactory::free_array<Klass*>(loader_data, local_interfaces);
 273   }
 274 }
 275 
 276 // This function deallocates the metadata and C heap pointers that the
 277 // InstanceKlass points to.
 278 void InstanceKlass::deallocate_contents(ClassLoaderData* loader_data) {
 279 
 280   // Orphan the mirror first, CMS thinks it's still live.
 281   if (java_mirror() != NULL) {
 282     java_lang_Class::set_klass(java_mirror(), NULL);
 283   }
 284 
 285   // Need to take this class off the class loader data list.
 286   loader_data->remove_class(this);
 287 
 288   // The array_klass for this class is created later, after error handling.
 289   // For class redefinition, we keep the original class so this scratch class
 290   // doesn't have an array class.  Either way, assert that there is nothing
 291   // to deallocate.
 292   assert(array_klasses() == NULL, "array classes shouldn't be created for this class yet");
 293 
 294   // Release C heap allocated data that this might point to, which includes
 295   // reference counting symbol names.
 296   release_C_heap_structures();
 297 
 298   deallocate_methods(loader_data, methods());
 299   set_methods(NULL);
 300 
 301   if (method_ordering() != NULL &&
 302       method_ordering() != Universe::the_empty_int_array() &&
 303       !method_ordering()->is_shared()) {
 304     MetadataFactory::free_array<int>(loader_data, method_ordering());
 305   }
 306   set_method_ordering(NULL);
 307 
 308   // default methods can be empty
 309   if (default_methods() != NULL &&
 310       default_methods() != Universe::the_empty_method_array() &&
 311       !default_methods()->is_shared()) {
 312     MetadataFactory::free_array<Method*>(loader_data, default_methods());
 313   }
 314   // Do NOT deallocate the default methods, they are owned by superinterfaces.
 315   set_default_methods(NULL);
 316 
 317   // default methods vtable indices can be empty
 318   if (default_vtable_indices() != NULL &&
 319       !default_vtable_indices()->is_shared()) {
 320     MetadataFactory::free_array<int>(loader_data, default_vtable_indices());
 321   }
 322   set_default_vtable_indices(NULL);
 323 
 324 
 325   // This array is in Klass, but remove it with the InstanceKlass since
 326   // this place would be the only caller and it can share memory with transitive
 327   // interfaces.
 328   if (secondary_supers() != NULL &&
 329       secondary_supers() != Universe::the_empty_klass_array() &&
 330       secondary_supers() != transitive_interfaces() &&
 331       !secondary_supers()->is_shared()) {
 332     MetadataFactory::free_array<Klass*>(loader_data, secondary_supers());
 333   }
 334   set_secondary_supers(NULL);
 335 
 336   deallocate_interfaces(loader_data, super(), local_interfaces(), transitive_interfaces());
 337   set_transitive_interfaces(NULL);
 338   set_local_interfaces(NULL);
 339 
 340   if (fields() != NULL && !fields()->is_shared()) {
 341     MetadataFactory::free_array<jushort>(loader_data, fields());
 342   }
 343   set_fields(NULL, 0);
 344 
 345   // If a method from a redefined class is using this constant pool, don't
 346   // delete it, yet.  The new class's previous version will point to this.
 347   if (constants() != NULL) {
 348     assert (!constants()->on_stack(), "shouldn't be called if anything is onstack");
 349     if (!constants()->is_shared()) {
 350       MetadataFactory::free_metadata(loader_data, constants());
 351     }
 352     // Delete any cached resolution errors for the constant pool
 353     SystemDictionary::delete_resolution_error(constants());
 354 
 355     set_constants(NULL);
 356   }
 357 
 358   if (inner_classes() != NULL &&
 359       inner_classes() != Universe::the_empty_short_array() &&
 360       !inner_classes()->is_shared()) {
 361     MetadataFactory::free_array<jushort>(loader_data, inner_classes());
 362   }
 363   set_inner_classes(NULL);
 364 
 365   // We should deallocate the Annotations instance if it's not in shared spaces.
 366   if (annotations() != NULL && !annotations()->is_shared()) {
 367     MetadataFactory::free_metadata(loader_data, annotations());
 368   }
 369   set_annotations(NULL);
 370 }
 371 
 372 bool InstanceKlass::should_be_initialized() const {
 373   return !is_initialized();
 374 }
 375 
 376 klassItable InstanceKlass::itable() const {
 377   return klassItable(const_cast<InstanceKlass*>(this));
 378 }
 379 
 380 void InstanceKlass::eager_initialize(Thread *thread) {
 381   if (!EagerInitialization) return;
 382 
 383   if (this->is_not_initialized()) {
 384     // abort if the the class has a class initializer
 385     if (this->class_initializer() != NULL) return;
 386 
 387     // abort if it is java.lang.Object (initialization is handled in genesis)
 388     Klass* super_klass = super();
 389     if (super_klass == NULL) return;
 390 
 391     // abort if the super class should be initialized
 392     if (!InstanceKlass::cast(super_klass)->is_initialized()) return;
 393 
 394     // call body to expose the this pointer
 395     eager_initialize_impl();
 396   }
 397 }
 398 
 399 // JVMTI spec thinks there are signers and protection domain in the
 400 // instanceKlass.  These accessors pretend these fields are there.
 401 // The hprof specification also thinks these fields are in InstanceKlass.
 402 oop InstanceKlass::protection_domain() const {
 403   // return the protection_domain from the mirror
 404   return java_lang_Class::protection_domain(java_mirror());
 405 }
 406 
 407 // To remove these from requires an incompatible change and CCC request.
 408 objArrayOop InstanceKlass::signers() const {
 409   // return the signers from the mirror
 410   return java_lang_Class::signers(java_mirror());
 411 }
 412 
 413 oop InstanceKlass::init_lock() const {
 414   // return the init lock from the mirror
 415   oop lock = java_lang_Class::init_lock(java_mirror());
 416   // Prevent reordering with any access of initialization state
 417   OrderAccess::loadload();
 418   assert((oop)lock != NULL || !is_not_initialized(), // initialized or in_error state
 419          "only fully initialized state can have a null lock");
 420   return lock;
 421 }
 422 
 423 // Set the initialization lock to null so the object can be GC'ed.  Any racing
 424 // threads to get this lock will see a null lock and will not lock.
 425 // That's okay because they all check for initialized state after getting
 426 // the lock and return.
 427 void InstanceKlass::fence_and_clear_init_lock() {
 428   // make sure previous stores are all done, notably the init_state.
 429   OrderAccess::storestore();
 430   java_lang_Class::set_init_lock(java_mirror(), NULL);
 431   assert(!is_not_initialized(), "class must be initialized now");
 432 }
 433 
 434 void InstanceKlass::eager_initialize_impl() {
 435   EXCEPTION_MARK;
 436   HandleMark hm(THREAD);
 437   Handle h_init_lock(THREAD, init_lock());
 438   ObjectLocker ol(h_init_lock, THREAD, init_lock() != NULL);
 439 
 440   // abort if someone beat us to the initialization
 441   if (!is_not_initialized()) return;  // note: not equivalent to is_initialized()
 442 
 443   ClassState old_state = init_state();
 444   link_class_impl(true, THREAD);
 445   if (HAS_PENDING_EXCEPTION) {
 446     CLEAR_PENDING_EXCEPTION;
 447     // Abort if linking the class throws an exception.
 448 
 449     // Use a test to avoid redundantly resetting the state if there's
 450     // no change.  Set_init_state() asserts that state changes make
 451     // progress, whereas here we might just be spinning in place.
 452     if (old_state != _init_state)
 453       set_init_state(old_state);
 454   } else {
 455     // linking successfull, mark class as initialized
 456     set_init_state(fully_initialized);
 457     fence_and_clear_init_lock();
 458     // trace
 459     if (log_is_enabled(Info, class, init)) {
 460       ResourceMark rm(THREAD);
 461       log_info(class, init)("[Initialized %s without side effects]", external_name());
 462     }
 463   }
 464 }
 465 
 466 
 467 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
 468 // process. The step comments refers to the procedure described in that section.
 469 // Note: implementation moved to static method to expose the this pointer.
 470 void InstanceKlass::initialize(TRAPS) {
 471   if (this->should_be_initialized()) {
 472     initialize_impl(CHECK);
 473     // Note: at this point the class may be initialized
 474     //       OR it may be in the state of being initialized
 475     //       in case of recursive initialization!
 476   } else {
 477     assert(is_initialized(), "sanity check");
 478   }
 479 }
 480 
 481 
 482 bool InstanceKlass::verify_code(bool throw_verifyerror, TRAPS) {
 483   // 1) Verify the bytecodes
 484   Verifier::Mode mode =
 485     throw_verifyerror ? Verifier::ThrowException : Verifier::NoException;
 486   return Verifier::verify(this, mode, should_verify_class(), THREAD);
 487 }
 488 
 489 
 490 // Used exclusively by the shared spaces dump mechanism to prevent
 491 // classes mapped into the shared regions in new VMs from appearing linked.
 492 
 493 void InstanceKlass::unlink_class() {
 494   assert(is_linked(), "must be linked");
 495   _init_state = loaded;
 496 }
 497 
 498 void InstanceKlass::link_class(TRAPS) {
 499   assert(is_loaded(), "must be loaded");
 500   if (!is_linked()) {
 501     link_class_impl(true, CHECK);
 502   }
 503 }
 504 
 505 // Called to verify that a class can link during initialization, without
 506 // throwing a VerifyError.
 507 bool InstanceKlass::link_class_or_fail(TRAPS) {
 508   assert(is_loaded(), "must be loaded");
 509   if (!is_linked()) {
 510     link_class_impl(false, CHECK_false);
 511   }
 512   return is_linked();
 513 }
 514 
 515 bool InstanceKlass::link_class_impl(bool throw_verifyerror, TRAPS) {
 516   if (DumpSharedSpaces && is_in_error_state()) {
 517     // This is for CDS dumping phase only -- we use the in_error_state to indicate that
 518     // the class has failed verification. Throwing the NoClassDefFoundError here is just
 519     // a convenient way to stop repeat attempts to verify the same (bad) class.
 520     //
 521     // Note that the NoClassDefFoundError is not part of the JLS, and should not be thrown
 522     // if we are executing Java code. This is not a problem for CDS dumping phase since
 523     // it doesn't execute any Java code.
 524     ResourceMark rm(THREAD);
 525     THROW_MSG_(vmSymbols::java_lang_NoClassDefFoundError(), external_name(), false);
 526   }
 527   // return if already verified
 528   if (is_linked()) {
 529     return true;
 530   }
 531 
 532   // Timing
 533   // timer handles recursion
 534   assert(THREAD->is_Java_thread(), "non-JavaThread in link_class_impl");
 535   JavaThread* jt = (JavaThread*)THREAD;
 536 
 537   // link super class before linking this class
 538   Klass* super_klass = super();
 539   if (super_klass != NULL) {
 540     if (super_klass->is_interface()) {  // check if super class is an interface
 541       ResourceMark rm(THREAD);
 542       Exceptions::fthrow(
 543         THREAD_AND_LOCATION,
 544         vmSymbols::java_lang_IncompatibleClassChangeError(),
 545         "class %s has interface %s as super class",
 546         external_name(),
 547         super_klass->external_name()
 548       );
 549       return false;
 550     }
 551 
 552     InstanceKlass* ik_super = InstanceKlass::cast(super_klass);
 553     ik_super->link_class_impl(throw_verifyerror, CHECK_false);
 554   }
 555 
 556   // link all interfaces implemented by this class before linking this class
 557   Array<Klass*>* interfaces = local_interfaces();
 558   int num_interfaces = interfaces->length();
 559   for (int index = 0; index < num_interfaces; index++) {
 560     InstanceKlass* interk = InstanceKlass::cast(interfaces->at(index));
 561     interk->link_class_impl(throw_verifyerror, CHECK_false);
 562   }
 563 
 564   // in case the class is linked in the process of linking its superclasses
 565   if (is_linked()) {
 566     return true;
 567   }
 568 
 569   // trace only the link time for this klass that includes
 570   // the verification time
 571   PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
 572                              ClassLoader::perf_class_link_selftime(),
 573                              ClassLoader::perf_classes_linked(),
 574                              jt->get_thread_stat()->perf_recursion_counts_addr(),
 575                              jt->get_thread_stat()->perf_timers_addr(),
 576                              PerfClassTraceTime::CLASS_LINK);
 577 
 578   // verification & rewriting
 579   {
 580     HandleMark hm(THREAD);
 581     Handle h_init_lock(THREAD, init_lock());
 582     ObjectLocker ol(h_init_lock, THREAD, init_lock() != NULL);
 583     // rewritten will have been set if loader constraint error found
 584     // on an earlier link attempt
 585     // don't verify or rewrite if already rewritten
 586     //
 587 
 588     if (!is_linked()) {
 589       if (!is_rewritten()) {
 590         {
 591           bool verify_ok = verify_code(throw_verifyerror, THREAD);
 592           if (!verify_ok) {
 593             return false;
 594           }
 595         }
 596 
 597         // Just in case a side-effect of verify linked this class already
 598         // (which can sometimes happen since the verifier loads classes
 599         // using custom class loaders, which are free to initialize things)
 600         if (is_linked()) {
 601           return true;
 602         }
 603 
 604         // also sets rewritten
 605         rewrite_class(CHECK_false);
 606       } else if (is_shared()) {
 607         SystemDictionaryShared::check_verification_constraints(this, CHECK_false);
 608       }
 609 
 610       // relocate jsrs and link methods after they are all rewritten
 611       link_methods(CHECK_false);
 612 
 613       // Initialize the vtable and interface table after
 614       // methods have been rewritten since rewrite may
 615       // fabricate new Method*s.
 616       // also does loader constraint checking
 617       //
 618       // initialize_vtable and initialize_itable need to be rerun for
 619       // a shared class if the class is not loaded by the NULL classloader.
 620       ClassLoaderData * loader_data = class_loader_data();
 621       if (!(is_shared() &&
 622             loader_data->is_the_null_class_loader_data())) {
 623         ResourceMark rm(THREAD);
 624         vtable().initialize_vtable(true, CHECK_false);
 625         itable().initialize_itable(true, CHECK_false);
 626       }
 627 #ifdef ASSERT
 628       else {
 629         vtable().verify(tty, true);
 630         // In case itable verification is ever added.
 631         // itable().verify(tty, true);
 632       }
 633 #endif
 634       set_init_state(linked);
 635       if (JvmtiExport::should_post_class_prepare()) {
 636         Thread *thread = THREAD;
 637         assert(thread->is_Java_thread(), "thread->is_Java_thread()");
 638         JvmtiExport::post_class_prepare((JavaThread *) thread, this);
 639       }
 640     }
 641   }
 642   return true;
 643 }
 644 
 645 
 646 // Rewrite the byte codes of all of the methods of a class.
 647 // The rewriter must be called exactly once. Rewriting must happen after
 648 // verification but before the first method of the class is executed.
 649 void InstanceKlass::rewrite_class(TRAPS) {
 650   assert(is_loaded(), "must be loaded");
 651   if (is_rewritten()) {
 652     assert(is_shared(), "rewriting an unshared class?");
 653     return;
 654   }
 655   Rewriter::rewrite(this, CHECK);
 656   set_rewritten();
 657 }
 658 
 659 // Now relocate and link method entry points after class is rewritten.
 660 // This is outside is_rewritten flag. In case of an exception, it can be
 661 // executed more than once.
 662 void InstanceKlass::link_methods(TRAPS) {
 663   int len = methods()->length();
 664   for (int i = len-1; i >= 0; i--) {
 665     methodHandle m(THREAD, methods()->at(i));
 666 
 667     // Set up method entry points for compiler and interpreter    .
 668     m->link_method(m, CHECK);
 669   }
 670 }
 671 
 672 // Eagerly initialize superinterfaces that declare default methods (concrete instance: any access)
 673 void InstanceKlass::initialize_super_interfaces(TRAPS) {
 674   assert (has_nonstatic_concrete_methods(), "caller should have checked this");
 675   for (int i = 0; i < local_interfaces()->length(); ++i) {
 676     Klass* iface = local_interfaces()->at(i);
 677     InstanceKlass* ik = InstanceKlass::cast(iface);
 678 
 679     // Initialization is depth first search ie. we start with top of the inheritance tree
 680     // has_nonstatic_concrete_methods drives searching superinterfaces since it
 681     // means has_nonstatic_concrete_methods in its superinterface hierarchy
 682     if (ik->has_nonstatic_concrete_methods()) {
 683       ik->initialize_super_interfaces(CHECK);
 684     }
 685 
 686     // Only initialize() interfaces that "declare" concrete methods.
 687     if (ik->should_be_initialized() && ik->declares_nonstatic_concrete_methods()) {
 688       ik->initialize(CHECK);
 689     }
 690   }
 691 }
 692 
 693 void InstanceKlass::initialize_impl(TRAPS) {
 694   HandleMark hm(THREAD);
 695 
 696   // Make sure klass is linked (verified) before initialization
 697   // A class could already be verified, since it has been reflected upon.
 698   link_class(CHECK);
 699 
 700   DTRACE_CLASSINIT_PROBE(required, -1);
 701 
 702   bool wait = false;
 703 
 704   // refer to the JVM book page 47 for description of steps
 705   // Step 1
 706   {
 707     Handle h_init_lock(THREAD, init_lock());
 708     ObjectLocker ol(h_init_lock, THREAD, init_lock() != NULL);
 709 
 710     Thread *self = THREAD; // it's passed the current thread
 711 
 712     // Step 2
 713     // If we were to use wait() instead of waitInterruptibly() then
 714     // we might end up throwing IE from link/symbol resolution sites
 715     // that aren't expected to throw.  This would wreak havoc.  See 6320309.
 716     while(is_being_initialized() && !is_reentrant_initialization(self)) {
 717         wait = true;
 718       ol.waitUninterruptibly(CHECK);
 719     }
 720 
 721     // Step 3
 722     if (is_being_initialized() && is_reentrant_initialization(self)) {
 723       DTRACE_CLASSINIT_PROBE_WAIT(recursive, -1, wait);
 724       return;
 725     }
 726 
 727     // Step 4
 728     if (is_initialized()) {
 729       DTRACE_CLASSINIT_PROBE_WAIT(concurrent, -1, wait);
 730       return;
 731     }
 732 
 733     // Step 5
 734     if (is_in_error_state()) {
 735       DTRACE_CLASSINIT_PROBE_WAIT(erroneous, -1, wait);
 736       ResourceMark rm(THREAD);
 737       const char* desc = "Could not initialize class ";
 738       const char* className = external_name();
 739       size_t msglen = strlen(desc) + strlen(className) + 1;
 740       char* message = NEW_RESOURCE_ARRAY(char, msglen);
 741       if (NULL == message) {
 742         // Out of memory: can't create detailed error message
 743         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), className);
 744       } else {
 745         jio_snprintf(message, msglen, "%s%s", desc, className);
 746         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), message);
 747       }
 748     }
 749 
 750     // Step 6
 751     set_init_state(being_initialized);
 752     set_init_thread(self);
 753   }
 754 
 755   // Step 7
 756   // Next, if C is a class rather than an interface, initialize it's super class and super
 757   // interfaces.
 758   if (!is_interface()) {
 759     Klass* super_klass = super();
 760     if (super_klass != NULL && super_klass->should_be_initialized()) {
 761       super_klass->initialize(THREAD);
 762     }
 763     // If C implements any interface that declares a non-static, concrete method,
 764     // the initialization of C triggers initialization of its super interfaces.
 765     // Only need to recurse if has_nonstatic_concrete_methods which includes declaring and
 766     // having a superinterface that declares, non-static, concrete methods
 767     if (!HAS_PENDING_EXCEPTION && has_nonstatic_concrete_methods()) {
 768       initialize_super_interfaces(THREAD);
 769     }
 770 
 771     // If any exceptions, complete abruptly, throwing the same exception as above.
 772     if (HAS_PENDING_EXCEPTION) {
 773       Handle e(THREAD, PENDING_EXCEPTION);
 774       CLEAR_PENDING_EXCEPTION;
 775       {
 776         EXCEPTION_MARK;
 777         // Locks object, set state, and notify all waiting threads
 778         set_initialization_state_and_notify(initialization_error, THREAD);
 779         CLEAR_PENDING_EXCEPTION;
 780       }
 781       DTRACE_CLASSINIT_PROBE_WAIT(super__failed, -1, wait);
 782       THROW_OOP(e());
 783     }
 784   }
 785 
 786 
 787   // Look for aot compiled methods for this klass, including class initializer.
 788   AOTLoader::load_for_klass(this, THREAD);
 789 
 790   // Step 8
 791   {
 792     assert(THREAD->is_Java_thread(), "non-JavaThread in initialize_impl");
 793     JavaThread* jt = (JavaThread*)THREAD;
 794     DTRACE_CLASSINIT_PROBE_WAIT(clinit, -1, wait);
 795     // Timer includes any side effects of class initialization (resolution,
 796     // etc), but not recursive entry into call_class_initializer().
 797     PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
 798                              ClassLoader::perf_class_init_selftime(),
 799                              ClassLoader::perf_classes_inited(),
 800                              jt->get_thread_stat()->perf_recursion_counts_addr(),
 801                              jt->get_thread_stat()->perf_timers_addr(),
 802                              PerfClassTraceTime::CLASS_CLINIT);
 803     call_class_initializer(THREAD);
 804   }
 805 
 806   // Step 9
 807   if (!HAS_PENDING_EXCEPTION) {
 808     set_initialization_state_and_notify(fully_initialized, CHECK);
 809     {
 810       debug_only(vtable().verify(tty, true);)
 811     }
 812   }
 813   else {
 814     // Step 10 and 11
 815     Handle e(THREAD, PENDING_EXCEPTION);
 816     CLEAR_PENDING_EXCEPTION;
 817     // JVMTI has already reported the pending exception
 818     // JVMTI internal flag reset is needed in order to report ExceptionInInitializerError
 819     JvmtiExport::clear_detected_exception((JavaThread*)THREAD);
 820     {
 821       EXCEPTION_MARK;
 822       set_initialization_state_and_notify(initialization_error, THREAD);
 823       CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, class initialization error is thrown below
 824       // JVMTI has already reported the pending exception
 825       // JVMTI internal flag reset is needed in order to report ExceptionInInitializerError
 826       JvmtiExport::clear_detected_exception((JavaThread*)THREAD);
 827     }
 828     DTRACE_CLASSINIT_PROBE_WAIT(error, -1, wait);
 829     if (e->is_a(SystemDictionary::Error_klass())) {
 830       THROW_OOP(e());
 831     } else {
 832       JavaCallArguments args(e);
 833       THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),
 834                 vmSymbols::throwable_void_signature(),
 835                 &args);
 836     }
 837   }
 838   DTRACE_CLASSINIT_PROBE_WAIT(end, -1, wait);
 839 }
 840 
 841 
 842 void InstanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
 843   Handle h_init_lock(THREAD, init_lock());
 844   if (init_lock() != NULL) {
 845     ObjectLocker ol(h_init_lock, THREAD);
 846     set_init_state(state);
 847     fence_and_clear_init_lock();
 848     ol.notify_all(CHECK);
 849   } else {
 850     assert(init_lock() != NULL, "The initialization state should never be set twice");
 851     set_init_state(state);
 852   }
 853 }
 854 
 855 // The embedded _implementor field can only record one implementor.
 856 // When there are more than one implementors, the _implementor field
 857 // is set to the interface Klass* itself. Following are the possible
 858 // values for the _implementor field:
 859 //   NULL                  - no implementor
 860 //   implementor Klass*    - one implementor
 861 //   self                  - more than one implementor
 862 //
 863 // The _implementor field only exists for interfaces.
 864 void InstanceKlass::add_implementor(Klass* k) {
 865   assert(Compile_lock->owned_by_self(), "");
 866   assert(is_interface(), "not interface");
 867   // Filter out my subinterfaces.
 868   // (Note: Interfaces are never on the subklass list.)
 869   if (InstanceKlass::cast(k)->is_interface()) return;
 870 
 871   // Filter out subclasses whose supers already implement me.
 872   // (Note: CHA must walk subclasses of direct implementors
 873   // in order to locate indirect implementors.)
 874   Klass* sk = k->super();
 875   if (sk != NULL && InstanceKlass::cast(sk)->implements_interface(this))
 876     // We only need to check one immediate superclass, since the
 877     // implements_interface query looks at transitive_interfaces.
 878     // Any supers of the super have the same (or fewer) transitive_interfaces.
 879     return;
 880 
 881   Klass* ik = implementor();
 882   if (ik == NULL) {
 883     set_implementor(k);
 884   } else if (ik != this) {
 885     // There is already an implementor. Use itself as an indicator of
 886     // more than one implementors.
 887     set_implementor(this);
 888   }
 889 
 890   // The implementor also implements the transitive_interfaces
 891   for (int index = 0; index < local_interfaces()->length(); index++) {
 892     InstanceKlass::cast(local_interfaces()->at(index))->add_implementor(k);
 893   }
 894 }
 895 
 896 void InstanceKlass::init_implementor() {
 897   if (is_interface()) {
 898     set_implementor(NULL);
 899   }
 900 }
 901 
 902 
 903 void InstanceKlass::process_interfaces(Thread *thread) {
 904   // link this class into the implementors list of every interface it implements
 905   for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
 906     assert(local_interfaces()->at(i)->is_klass(), "must be a klass");
 907     InstanceKlass* interf = InstanceKlass::cast(local_interfaces()->at(i));
 908     assert(interf->is_interface(), "expected interface");
 909     interf->add_implementor(this);
 910   }
 911 }
 912 
 913 bool InstanceKlass::can_be_primary_super_slow() const {
 914   if (is_interface())
 915     return false;
 916   else
 917     return Klass::can_be_primary_super_slow();
 918 }
 919 
 920 GrowableArray<Klass*>* InstanceKlass::compute_secondary_supers(int num_extra_slots) {
 921   // The secondaries are the implemented interfaces.
 922   Array<Klass*>* interfaces = transitive_interfaces();
 923   int num_secondaries = num_extra_slots + interfaces->length();
 924   if (num_secondaries == 0) {
 925     // Must share this for correct bootstrapping!
 926     set_secondary_supers(Universe::the_empty_klass_array());
 927     return NULL;
 928   } else if (num_extra_slots == 0) {
 929     // The secondary super list is exactly the same as the transitive interfaces.
 930     // Redefine classes has to be careful not to delete this!
 931     set_secondary_supers(interfaces);
 932     return NULL;
 933   } else {
 934     // Copy transitive interfaces to a temporary growable array to be constructed
 935     // into the secondary super list with extra slots.
 936     GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(interfaces->length());
 937     for (int i = 0; i < interfaces->length(); i++) {
 938       secondaries->push(interfaces->at(i));
 939     }
 940     return secondaries;
 941   }
 942 }
 943 
 944 bool InstanceKlass::compute_is_subtype_of(Klass* k) {
 945   if (k->is_interface()) {
 946     return implements_interface(k);
 947   } else {
 948     return Klass::compute_is_subtype_of(k);
 949   }
 950 }
 951 
 952 bool InstanceKlass::implements_interface(Klass* k) const {
 953   if (this == k) return true;
 954   assert(k->is_interface(), "should be an interface class");
 955   for (int i = 0; i < transitive_interfaces()->length(); i++) {
 956     if (transitive_interfaces()->at(i) == k) {
 957       return true;
 958     }
 959   }
 960   return false;
 961 }
 962 
 963 bool InstanceKlass::is_same_or_direct_interface(Klass *k) const {
 964   // Verify direct super interface
 965   if (this == k) return true;
 966   assert(k->is_interface(), "should be an interface class");
 967   for (int i = 0; i < local_interfaces()->length(); i++) {
 968     if (local_interfaces()->at(i) == k) {
 969       return true;
 970     }
 971   }
 972   return false;
 973 }
 974 
 975 objArrayOop InstanceKlass::allocate_objArray(int n, int length, TRAPS) {
 976   if (length < 0) THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
 977   if (length > arrayOopDesc::max_array_length(T_OBJECT)) {
 978     report_java_out_of_memory("Requested array size exceeds VM limit");
 979     JvmtiExport::post_array_size_exhausted();
 980     THROW_OOP_0(Universe::out_of_memory_error_array_size());
 981   }
 982   int size = objArrayOopDesc::object_size(length);
 983   Klass* ak = array_klass(n, CHECK_NULL);
 984   objArrayOop o =
 985     (objArrayOop)CollectedHeap::array_allocate(ak, size, length, CHECK_NULL);
 986   return o;
 987 }
 988 
 989 instanceOop InstanceKlass::register_finalizer(instanceOop i, TRAPS) {
 990   if (TraceFinalizerRegistration) {
 991     tty->print("Registered ");
 992     i->print_value_on(tty);
 993     tty->print_cr(" (" INTPTR_FORMAT ") as finalizable", p2i(i));
 994   }
 995   instanceHandle h_i(THREAD, i);
 996   // Pass the handle as argument, JavaCalls::call expects oop as jobjects
 997   JavaValue result(T_VOID);
 998   JavaCallArguments args(h_i);
 999   methodHandle mh (THREAD, Universe::finalizer_register_method());
1000   JavaCalls::call(&result, mh, &args, CHECK_NULL);
1001   return h_i();
1002 }
1003 
1004 instanceOop InstanceKlass::allocate_instance(TRAPS) {
1005   bool has_finalizer_flag = has_finalizer(); // Query before possible GC
1006   int size = size_helper();  // Query before forming handle.
1007 
1008   instanceOop i;
1009 
1010   i = (instanceOop)CollectedHeap::obj_allocate(this, size, CHECK_NULL);
1011   if (has_finalizer_flag && !RegisterFinalizersAtInit) {
1012     i = register_finalizer(i, CHECK_NULL);
1013   }
1014   return i;
1015 }
1016 
1017 void InstanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
1018   if (is_interface() || is_abstract()) {
1019     ResourceMark rm(THREAD);
1020     THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
1021               : vmSymbols::java_lang_InstantiationException(), external_name());
1022   }
1023   if (this == SystemDictionary::Class_klass()) {
1024     ResourceMark rm(THREAD);
1025     THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
1026               : vmSymbols::java_lang_IllegalAccessException(), external_name());
1027   }
1028 }
1029 
1030 Klass* InstanceKlass::array_klass_impl(bool or_null, int n, TRAPS) {
1031   // Need load-acquire for lock-free read
1032   if (array_klasses_acquire() == NULL) {
1033     if (or_null) return NULL;
1034 
1035     ResourceMark rm;
1036     JavaThread *jt = (JavaThread *)THREAD;
1037     {
1038       // Atomic creation of array_klasses
1039       MutexLocker mc(Compile_lock, THREAD);   // for vtables
1040       MutexLocker ma(MultiArray_lock, THREAD);
1041 
1042       // Check if update has already taken place
1043       if (array_klasses() == NULL) {
1044         Klass*    k = ObjArrayKlass::allocate_objArray_klass(class_loader_data(), 1, this, CHECK_NULL);
1045         // use 'release' to pair with lock-free load
1046         release_set_array_klasses(k);
1047       }
1048     }
1049   }
1050   // _this will always be set at this point
1051   ObjArrayKlass* oak = (ObjArrayKlass*)array_klasses();
1052   if (or_null) {
1053     return oak->array_klass_or_null(n);
1054   }
1055   return oak->array_klass(n, THREAD);
1056 }
1057 
1058 Klass* InstanceKlass::array_klass_impl(bool or_null, TRAPS) {
1059   return array_klass_impl(or_null, 1, THREAD);
1060 }
1061 
1062 static int call_class_initializer_counter = 0;   // for debugging
1063 
1064 Method* InstanceKlass::class_initializer() const {
1065   Method* clinit = find_method(
1066       vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
1067   if (clinit != NULL && clinit->has_valid_initializer_flags()) {
1068     return clinit;
1069   }
1070   return NULL;
1071 }
1072 
1073 void InstanceKlass::call_class_initializer(TRAPS) {
1074   if (ReplayCompiles &&
1075       (ReplaySuppressInitializers == 1 ||
1076        ReplaySuppressInitializers >= 2 && class_loader() != NULL)) {
1077     // Hide the existence of the initializer for the purpose of replaying the compile
1078     return;
1079   }
1080 
1081   methodHandle h_method(THREAD, class_initializer());
1082   assert(!is_initialized(), "we cannot initialize twice");
1083   if (log_is_enabled(Info, class, init)) {
1084     ResourceMark rm;
1085     outputStream* log = Log(class, init)::info_stream();
1086     log->print("%d Initializing ", call_class_initializer_counter++);
1087     name()->print_value_on(log);
1088     log->print_cr("%s (" INTPTR_FORMAT ")", h_method() == NULL ? "(no method)" : "", p2i(this));
1089   }
1090   if (h_method() != NULL) {
1091     JavaCallArguments args; // No arguments
1092     JavaValue result(T_VOID);
1093     JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
1094   }
1095 }
1096 
1097 
1098 void InstanceKlass::mask_for(const methodHandle& method, int bci,
1099   InterpreterOopMap* entry_for) {
1100   // Lazily create the _oop_map_cache at first request
1101   // Lock-free access requires load_ptr_acquire.
1102   OopMapCache* oop_map_cache =
1103       static_cast<OopMapCache*>(OrderAccess::load_ptr_acquire(&_oop_map_cache));
1104   if (oop_map_cache == NULL) {
1105     MutexLocker x(OopMapCacheAlloc_lock);
1106     // Check if _oop_map_cache was allocated while we were waiting for this lock
1107     if ((oop_map_cache = _oop_map_cache) == NULL) {
1108       oop_map_cache = new OopMapCache();
1109       // Ensure _oop_map_cache is stable, since it is examined without a lock
1110       OrderAccess::release_store_ptr(&_oop_map_cache, oop_map_cache);
1111     }
1112   }
1113   // _oop_map_cache is constant after init; lookup below does its own locking.
1114   oop_map_cache->lookup(method, bci, entry_for);
1115 }
1116 
1117 
1118 bool InstanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1119   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1120     Symbol* f_name = fs.name();
1121     Symbol* f_sig  = fs.signature();
1122     if (f_name == name && f_sig == sig) {
1123       fd->reinitialize(const_cast<InstanceKlass*>(this), fs.index());
1124       return true;
1125     }
1126   }
1127   return false;
1128 }
1129 
1130 
1131 Klass* InstanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1132   const int n = local_interfaces()->length();
1133   for (int i = 0; i < n; i++) {
1134     Klass* intf1 = local_interfaces()->at(i);
1135     assert(intf1->is_interface(), "just checking type");
1136     // search for field in current interface
1137     if (InstanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {
1138       assert(fd->is_static(), "interface field must be static");
1139       return intf1;
1140     }
1141     // search for field in direct superinterfaces
1142     Klass* intf2 = InstanceKlass::cast(intf1)->find_interface_field(name, sig, fd);
1143     if (intf2 != NULL) return intf2;
1144   }
1145   // otherwise field lookup fails
1146   return NULL;
1147 }
1148 
1149 
1150 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1151   // search order according to newest JVM spec (5.4.3.2, p.167).
1152   // 1) search for field in current klass
1153   if (find_local_field(name, sig, fd)) {
1154     return const_cast<InstanceKlass*>(this);
1155   }
1156   // 2) search for field recursively in direct superinterfaces
1157   { Klass* intf = find_interface_field(name, sig, fd);
1158     if (intf != NULL) return intf;
1159   }
1160   // 3) apply field lookup recursively if superclass exists
1161   { Klass* supr = super();
1162     if (supr != NULL) return InstanceKlass::cast(supr)->find_field(name, sig, fd);
1163   }
1164   // 4) otherwise field lookup fails
1165   return NULL;
1166 }
1167 
1168 
1169 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {
1170   // search order according to newest JVM spec (5.4.3.2, p.167).
1171   // 1) search for field in current klass
1172   if (find_local_field(name, sig, fd)) {
1173     if (fd->is_static() == is_static) return const_cast<InstanceKlass*>(this);
1174   }
1175   // 2) search for field recursively in direct superinterfaces
1176   if (is_static) {
1177     Klass* intf = find_interface_field(name, sig, fd);
1178     if (intf != NULL) return intf;
1179   }
1180   // 3) apply field lookup recursively if superclass exists
1181   { Klass* supr = super();
1182     if (supr != NULL) return InstanceKlass::cast(supr)->find_field(name, sig, is_static, fd);
1183   }
1184   // 4) otherwise field lookup fails
1185   return NULL;
1186 }
1187 
1188 
1189 bool InstanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
1190   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1191     if (fs.offset() == offset) {
1192       fd->reinitialize(const_cast<InstanceKlass*>(this), fs.index());
1193       if (fd->is_static() == is_static) return true;
1194     }
1195   }
1196   return false;
1197 }
1198 
1199 
1200 bool InstanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
1201   Klass* klass = const_cast<InstanceKlass*>(this);
1202   while (klass != NULL) {
1203     if (InstanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {
1204       return true;
1205     }
1206     klass = klass->super();
1207   }
1208   return false;
1209 }
1210 
1211 
1212 void InstanceKlass::methods_do(void f(Method* method)) {
1213   // Methods aren't stable until they are loaded.  This can be read outside
1214   // a lock through the ClassLoaderData for profiling
1215   if (!is_loaded()) {
1216     return;
1217   }
1218 
1219   int len = methods()->length();
1220   for (int index = 0; index < len; index++) {
1221     Method* m = methods()->at(index);
1222     assert(m->is_method(), "must be method");
1223     f(m);
1224   }
1225 }
1226 
1227 
1228 void InstanceKlass::do_local_static_fields(FieldClosure* cl) {
1229   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1230     if (fs.access_flags().is_static()) {
1231       fieldDescriptor& fd = fs.field_descriptor();
1232       cl->do_field(&fd);
1233     }
1234   }
1235 }
1236 
1237 
1238 void InstanceKlass::do_local_static_fields(void f(fieldDescriptor*, Handle, TRAPS), Handle mirror, TRAPS) {
1239   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1240     if (fs.access_flags().is_static()) {
1241       fieldDescriptor& fd = fs.field_descriptor();
1242       f(&fd, mirror, CHECK);
1243     }
1244   }
1245 }
1246 
1247 
1248 static int compare_fields_by_offset(int* a, int* b) {
1249   return a[0] - b[0];
1250 }
1251 
1252 void InstanceKlass::do_nonstatic_fields(FieldClosure* cl) {
1253   InstanceKlass* super = superklass();
1254   if (super != NULL) {
1255     super->do_nonstatic_fields(cl);
1256   }
1257   fieldDescriptor fd;
1258   int length = java_fields_count();
1259   // In DebugInfo nonstatic fields are sorted by offset.
1260   int* fields_sorted = NEW_C_HEAP_ARRAY(int, 2*(length+1), mtClass);
1261   int j = 0;
1262   for (int i = 0; i < length; i += 1) {
1263     fd.reinitialize(this, i);
1264     if (!fd.is_static()) {
1265       fields_sorted[j + 0] = fd.offset();
1266       fields_sorted[j + 1] = i;
1267       j += 2;
1268     }
1269   }
1270   if (j > 0) {
1271     length = j;
1272     // _sort_Fn is defined in growableArray.hpp.
1273     qsort(fields_sorted, length/2, 2*sizeof(int), (_sort_Fn)compare_fields_by_offset);
1274     for (int i = 0; i < length; i += 2) {
1275       fd.reinitialize(this, fields_sorted[i + 1]);
1276       assert(!fd.is_static() && fd.offset() == fields_sorted[i], "only nonstatic fields");
1277       cl->do_field(&fd);
1278     }
1279   }
1280   FREE_C_HEAP_ARRAY(int, fields_sorted);
1281 }
1282 
1283 
1284 void InstanceKlass::array_klasses_do(void f(Klass* k, TRAPS), TRAPS) {
1285   if (array_klasses() != NULL)
1286     ArrayKlass::cast(array_klasses())->array_klasses_do(f, THREAD);
1287 }
1288 
1289 void InstanceKlass::array_klasses_do(void f(Klass* k)) {
1290   if (array_klasses() != NULL)
1291     ArrayKlass::cast(array_klasses())->array_klasses_do(f);
1292 }
1293 
1294 #ifdef ASSERT
1295 static int linear_search(const Array<Method*>* methods,
1296                          const Symbol* name,
1297                          const Symbol* signature) {
1298   const int len = methods->length();
1299   for (int index = 0; index < len; index++) {
1300     const Method* const m = methods->at(index);
1301     assert(m->is_method(), "must be method");
1302     if (m->signature() == signature && m->name() == name) {
1303        return index;
1304     }
1305   }
1306   return -1;
1307 }
1308 #endif
1309 
1310 static int binary_search(const Array<Method*>* methods, const Symbol* name) {
1311   int len = methods->length();
1312   // methods are sorted, so do binary search
1313   int l = 0;
1314   int h = len - 1;
1315   while (l <= h) {
1316     int mid = (l + h) >> 1;
1317     Method* m = methods->at(mid);
1318     assert(m->is_method(), "must be method");
1319     int res = m->name()->fast_compare(name);
1320     if (res == 0) {
1321       return mid;
1322     } else if (res < 0) {
1323       l = mid + 1;
1324     } else {
1325       h = mid - 1;
1326     }
1327   }
1328   return -1;
1329 }
1330 
1331 // find_method looks up the name/signature in the local methods array
1332 Method* InstanceKlass::find_method(const Symbol* name,
1333                                    const Symbol* signature) const {
1334   return find_method_impl(name, signature, find_overpass, find_static, find_private);
1335 }
1336 
1337 Method* InstanceKlass::find_method_impl(const Symbol* name,
1338                                         const Symbol* signature,
1339                                         OverpassLookupMode overpass_mode,
1340                                         StaticLookupMode static_mode,
1341                                         PrivateLookupMode private_mode) const {
1342   return InstanceKlass::find_method_impl(methods(),
1343                                          name,
1344                                          signature,
1345                                          overpass_mode,
1346                                          static_mode,
1347                                          private_mode);
1348 }
1349 
1350 // find_instance_method looks up the name/signature in the local methods array
1351 // and skips over static methods
1352 Method* InstanceKlass::find_instance_method(const Array<Method*>* methods,
1353                                             const Symbol* name,
1354                                             const Symbol* signature) {
1355   Method* const meth = InstanceKlass::find_method_impl(methods,
1356                                                  name,
1357                                                  signature,
1358                                                  find_overpass,
1359                                                  skip_static,
1360                                                  find_private);
1361   assert(((meth == NULL) || !meth->is_static()),
1362     "find_instance_method should have skipped statics");
1363   return meth;
1364 }
1365 
1366 // find_instance_method looks up the name/signature in the local methods array
1367 // and skips over static methods
1368 Method* InstanceKlass::find_instance_method(const Symbol* name, const Symbol* signature) const {
1369   return InstanceKlass::find_instance_method(methods(), name, signature);
1370 }
1371 
1372 // Find looks up the name/signature in the local methods array
1373 // and filters on the overpass, static and private flags
1374 // This returns the first one found
1375 // note that the local methods array can have up to one overpass, one static
1376 // and one instance (private or not) with the same name/signature
1377 Method* InstanceKlass::find_local_method(const Symbol* name,
1378                                          const Symbol* signature,
1379                                          OverpassLookupMode overpass_mode,
1380                                          StaticLookupMode static_mode,
1381                                          PrivateLookupMode private_mode) const {
1382   return InstanceKlass::find_method_impl(methods(),
1383                                          name,
1384                                          signature,
1385                                          overpass_mode,
1386                                          static_mode,
1387                                          private_mode);
1388 }
1389 
1390 // Find looks up the name/signature in the local methods array
1391 // and filters on the overpass, static and private flags
1392 // This returns the first one found
1393 // note that the local methods array can have up to one overpass, one static
1394 // and one instance (private or not) with the same name/signature
1395 Method* InstanceKlass::find_local_method(const Array<Method*>* methods,
1396                                          const Symbol* name,
1397                                          const Symbol* signature,
1398                                          OverpassLookupMode overpass_mode,
1399                                          StaticLookupMode static_mode,
1400                                          PrivateLookupMode private_mode) {
1401   return InstanceKlass::find_method_impl(methods,
1402                                          name,
1403                                          signature,
1404                                          overpass_mode,
1405                                          static_mode,
1406                                          private_mode);
1407 }
1408 
1409 Method* InstanceKlass::find_method(const Array<Method*>* methods,
1410                                    const Symbol* name,
1411                                    const Symbol* signature) {
1412   return InstanceKlass::find_method_impl(methods,
1413                                          name,
1414                                          signature,
1415                                          find_overpass,
1416                                          find_static,
1417                                          find_private);
1418 }
1419 
1420 Method* InstanceKlass::find_method_impl(const Array<Method*>* methods,
1421                                         const Symbol* name,
1422                                         const Symbol* signature,
1423                                         OverpassLookupMode overpass_mode,
1424                                         StaticLookupMode static_mode,
1425                                         PrivateLookupMode private_mode) {
1426   int hit = find_method_index(methods, name, signature, overpass_mode, static_mode, private_mode);
1427   return hit >= 0 ? methods->at(hit): NULL;
1428 }
1429 
1430 // true if method matches signature and conforms to skipping_X conditions.
1431 static bool method_matches(const Method* m,
1432                            const Symbol* signature,
1433                            bool skipping_overpass,
1434                            bool skipping_static,
1435                            bool skipping_private) {
1436   return ((m->signature() == signature) &&
1437     (!skipping_overpass || !m->is_overpass()) &&
1438     (!skipping_static || !m->is_static()) &&
1439     (!skipping_private || !m->is_private()));
1440 }
1441 
1442 // Used directly for default_methods to find the index into the
1443 // default_vtable_indices, and indirectly by find_method
1444 // find_method_index looks in the local methods array to return the index
1445 // of the matching name/signature. If, overpass methods are being ignored,
1446 // the search continues to find a potential non-overpass match.  This capability
1447 // is important during method resolution to prefer a static method, for example,
1448 // over an overpass method.
1449 // There is the possibility in any _method's array to have the same name/signature
1450 // for a static method, an overpass method and a local instance method
1451 // To correctly catch a given method, the search criteria may need
1452 // to explicitly skip the other two. For local instance methods, it
1453 // is often necessary to skip private methods
1454 int InstanceKlass::find_method_index(const Array<Method*>* methods,
1455                                      const Symbol* name,
1456                                      const Symbol* signature,
1457                                      OverpassLookupMode overpass_mode,
1458                                      StaticLookupMode static_mode,
1459                                      PrivateLookupMode private_mode) {
1460   const bool skipping_overpass = (overpass_mode == skip_overpass);
1461   const bool skipping_static = (static_mode == skip_static);
1462   const bool skipping_private = (private_mode == skip_private);
1463   const int hit = binary_search(methods, name);
1464   if (hit != -1) {
1465     const Method* const m = methods->at(hit);
1466 
1467     // Do linear search to find matching signature.  First, quick check
1468     // for common case, ignoring overpasses if requested.
1469     if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
1470           return hit;
1471     }
1472 
1473     // search downwards through overloaded methods
1474     int i;
1475     for (i = hit - 1; i >= 0; --i) {
1476         const Method* const m = methods->at(i);
1477         assert(m->is_method(), "must be method");
1478         if (m->name() != name) {
1479           break;
1480         }
1481         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
1482           return i;
1483         }
1484     }
1485     // search upwards
1486     for (i = hit + 1; i < methods->length(); ++i) {
1487         const Method* const m = methods->at(i);
1488         assert(m->is_method(), "must be method");
1489         if (m->name() != name) {
1490           break;
1491         }
1492         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
1493           return i;
1494         }
1495     }
1496     // not found
1497 #ifdef ASSERT
1498     const int index = (skipping_overpass || skipping_static || skipping_private) ? -1 :
1499       linear_search(methods, name, signature);
1500     assert(-1 == index, "binary search should have found entry %d", index);
1501 #endif
1502   }
1503   return -1;
1504 }
1505 
1506 int InstanceKlass::find_method_by_name(const Symbol* name, int* end) const {
1507   return find_method_by_name(methods(), name, end);
1508 }
1509 
1510 int InstanceKlass::find_method_by_name(const Array<Method*>* methods,
1511                                        const Symbol* name,
1512                                        int* end_ptr) {
1513   assert(end_ptr != NULL, "just checking");
1514   int start = binary_search(methods, name);
1515   int end = start + 1;
1516   if (start != -1) {
1517     while (start - 1 >= 0 && (methods->at(start - 1))->name() == name) --start;
1518     while (end < methods->length() && (methods->at(end))->name() == name) ++end;
1519     *end_ptr = end;
1520     return start;
1521   }
1522   return -1;
1523 }
1524 
1525 // uncached_lookup_method searches both the local class methods array and all
1526 // superclasses methods arrays, skipping any overpass methods in superclasses.
1527 Method* InstanceKlass::uncached_lookup_method(const Symbol* name,
1528                                               const Symbol* signature,
1529                                               OverpassLookupMode overpass_mode) const {
1530   OverpassLookupMode overpass_local_mode = overpass_mode;
1531   const Klass* klass = this;
1532   while (klass != NULL) {
1533     Method* const method = InstanceKlass::cast(klass)->find_method_impl(name,
1534                                                                         signature,
1535                                                                         overpass_local_mode,
1536                                                                         find_static,
1537                                                                         find_private);
1538     if (method != NULL) {
1539       return method;
1540     }
1541     klass = klass->super();
1542     overpass_local_mode = skip_overpass;   // Always ignore overpass methods in superclasses
1543   }
1544   return NULL;
1545 }
1546 
1547 #ifdef ASSERT
1548 // search through class hierarchy and return true if this class or
1549 // one of the superclasses was redefined
1550 bool InstanceKlass::has_redefined_this_or_super() const {
1551   const Klass* klass = this;
1552   while (klass != NULL) {
1553     if (InstanceKlass::cast(klass)->has_been_redefined()) {
1554       return true;
1555     }
1556     klass = klass->super();
1557   }
1558   return false;
1559 }
1560 #endif
1561 
1562 // lookup a method in the default methods list then in all transitive interfaces
1563 // Do NOT return private or static methods
1564 Method* InstanceKlass::lookup_method_in_ordered_interfaces(Symbol* name,
1565                                                          Symbol* signature) const {
1566   Method* m = NULL;
1567   if (default_methods() != NULL) {
1568     m = find_method(default_methods(), name, signature);
1569   }
1570   // Look up interfaces
1571   if (m == NULL) {
1572     m = lookup_method_in_all_interfaces(name, signature, find_defaults);
1573   }
1574   return m;
1575 }
1576 
1577 // lookup a method in all the interfaces that this class implements
1578 // Do NOT return private or static methods, new in JDK8 which are not externally visible
1579 // They should only be found in the initial InterfaceMethodRef
1580 Method* InstanceKlass::lookup_method_in_all_interfaces(Symbol* name,
1581                                                        Symbol* signature,
1582                                                        DefaultsLookupMode defaults_mode) const {
1583   Array<Klass*>* all_ifs = transitive_interfaces();
1584   int num_ifs = all_ifs->length();
1585   InstanceKlass *ik = NULL;
1586   for (int i = 0; i < num_ifs; i++) {
1587     ik = InstanceKlass::cast(all_ifs->at(i));
1588     Method* m = ik->lookup_method(name, signature);
1589     if (m != NULL && m->is_public() && !m->is_static() &&
1590         ((defaults_mode != skip_defaults) || !m->is_default_method())) {
1591       return m;
1592     }
1593   }
1594   return NULL;
1595 }
1596 
1597 /* jni_id_for_impl for jfieldIds only */
1598 JNIid* InstanceKlass::jni_id_for_impl(int offset) {
1599   MutexLocker ml(JfieldIdCreation_lock);
1600   // Retry lookup after we got the lock
1601   JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
1602   if (probe == NULL) {
1603     // Slow case, allocate new static field identifier
1604     probe = new JNIid(this, offset, jni_ids());
1605     set_jni_ids(probe);
1606   }
1607   return probe;
1608 }
1609 
1610 
1611 /* jni_id_for for jfieldIds only */
1612 JNIid* InstanceKlass::jni_id_for(int offset) {
1613   JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
1614   if (probe == NULL) {
1615     probe = jni_id_for_impl(offset);
1616   }
1617   return probe;
1618 }
1619 
1620 u2 InstanceKlass::enclosing_method_data(int offset) const {
1621   const Array<jushort>* const inner_class_list = inner_classes();
1622   if (inner_class_list == NULL) {
1623     return 0;
1624   }
1625   const int length = inner_class_list->length();
1626   if (length % inner_class_next_offset == 0) {
1627     return 0;
1628   }
1629   const int index = length - enclosing_method_attribute_size;
1630   assert(offset < enclosing_method_attribute_size, "invalid offset");
1631   return inner_class_list->at(index + offset);
1632 }
1633 
1634 void InstanceKlass::set_enclosing_method_indices(u2 class_index,
1635                                                  u2 method_index) {
1636   Array<jushort>* inner_class_list = inner_classes();
1637   assert (inner_class_list != NULL, "_inner_classes list is not set up");
1638   int length = inner_class_list->length();
1639   if (length % inner_class_next_offset == enclosing_method_attribute_size) {
1640     int index = length - enclosing_method_attribute_size;
1641     inner_class_list->at_put(
1642       index + enclosing_method_class_index_offset, class_index);
1643     inner_class_list->at_put(
1644       index + enclosing_method_method_index_offset, method_index);
1645   }
1646 }
1647 
1648 // Lookup or create a jmethodID.
1649 // This code is called by the VMThread and JavaThreads so the
1650 // locking has to be done very carefully to avoid deadlocks
1651 // and/or other cache consistency problems.
1652 //
1653 jmethodID InstanceKlass::get_jmethod_id(const methodHandle& method_h) {
1654   size_t idnum = (size_t)method_h->method_idnum();
1655   jmethodID* jmeths = methods_jmethod_ids_acquire();
1656   size_t length = 0;
1657   jmethodID id = NULL;
1658 
1659   // We use a double-check locking idiom here because this cache is
1660   // performance sensitive. In the normal system, this cache only
1661   // transitions from NULL to non-NULL which is safe because we use
1662   // release_set_methods_jmethod_ids() to advertise the new cache.
1663   // A partially constructed cache should never be seen by a racing
1664   // thread. We also use release_store_ptr() to save a new jmethodID
1665   // in the cache so a partially constructed jmethodID should never be
1666   // seen either. Cache reads of existing jmethodIDs proceed without a
1667   // lock, but cache writes of a new jmethodID requires uniqueness and
1668   // creation of the cache itself requires no leaks so a lock is
1669   // generally acquired in those two cases.
1670   //
1671   // If the RedefineClasses() API has been used, then this cache can
1672   // grow and we'll have transitions from non-NULL to bigger non-NULL.
1673   // Cache creation requires no leaks and we require safety between all
1674   // cache accesses and freeing of the old cache so a lock is generally
1675   // acquired when the RedefineClasses() API has been used.
1676 
1677   if (jmeths != NULL) {
1678     // the cache already exists
1679     if (!idnum_can_increment()) {
1680       // the cache can't grow so we can just get the current values
1681       get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1682     } else {
1683       // cache can grow so we have to be more careful
1684       if (Threads::number_of_threads() == 0 ||
1685           SafepointSynchronize::is_at_safepoint()) {
1686         // we're single threaded or at a safepoint - no locking needed
1687         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1688       } else {
1689         MutexLocker ml(JmethodIdCreation_lock);
1690         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1691       }
1692     }
1693   }
1694   // implied else:
1695   // we need to allocate a cache so default length and id values are good
1696 
1697   if (jmeths == NULL ||   // no cache yet
1698       length <= idnum ||  // cache is too short
1699       id == NULL) {       // cache doesn't contain entry
1700 
1701     // This function can be called by the VMThread so we have to do all
1702     // things that might block on a safepoint before grabbing the lock.
1703     // Otherwise, we can deadlock with the VMThread or have a cache
1704     // consistency issue. These vars keep track of what we might have
1705     // to free after the lock is dropped.
1706     jmethodID  to_dealloc_id     = NULL;
1707     jmethodID* to_dealloc_jmeths = NULL;
1708 
1709     // may not allocate new_jmeths or use it if we allocate it
1710     jmethodID* new_jmeths = NULL;
1711     if (length <= idnum) {
1712       // allocate a new cache that might be used
1713       size_t size = MAX2(idnum+1, (size_t)idnum_allocated_count());
1714       new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1, mtClass);
1715       memset(new_jmeths, 0, (size+1)*sizeof(jmethodID));
1716       // cache size is stored in element[0], other elements offset by one
1717       new_jmeths[0] = (jmethodID)size;
1718     }
1719 
1720     // allocate a new jmethodID that might be used
1721     jmethodID new_id = NULL;
1722     if (method_h->is_old() && !method_h->is_obsolete()) {
1723       // The method passed in is old (but not obsolete), we need to use the current version
1724       Method* current_method = method_with_idnum((int)idnum);
1725       assert(current_method != NULL, "old and but not obsolete, so should exist");
1726       new_id = Method::make_jmethod_id(class_loader_data(), current_method);
1727     } else {
1728       // It is the current version of the method or an obsolete method,
1729       // use the version passed in
1730       new_id = Method::make_jmethod_id(class_loader_data(), method_h());
1731     }
1732 
1733     if (Threads::number_of_threads() == 0 ||
1734         SafepointSynchronize::is_at_safepoint()) {
1735       // we're single threaded or at a safepoint - no locking needed
1736       id = get_jmethod_id_fetch_or_update(idnum, new_id, new_jmeths,
1737                                           &to_dealloc_id, &to_dealloc_jmeths);
1738     } else {
1739       MutexLocker ml(JmethodIdCreation_lock);
1740       id = get_jmethod_id_fetch_or_update(idnum, new_id, new_jmeths,
1741                                           &to_dealloc_id, &to_dealloc_jmeths);
1742     }
1743 
1744     // The lock has been dropped so we can free resources.
1745     // Free up either the old cache or the new cache if we allocated one.
1746     if (to_dealloc_jmeths != NULL) {
1747       FreeHeap(to_dealloc_jmeths);
1748     }
1749     // free up the new ID since it wasn't needed
1750     if (to_dealloc_id != NULL) {
1751       Method::destroy_jmethod_id(class_loader_data(), to_dealloc_id);
1752     }
1753   }
1754   return id;
1755 }
1756 
1757 // Figure out how many jmethodIDs haven't been allocated, and make
1758 // sure space for them is pre-allocated.  This makes getting all
1759 // method ids much, much faster with classes with more than 8
1760 // methods, and has a *substantial* effect on performance with jvmti
1761 // code that loads all jmethodIDs for all classes.
1762 void InstanceKlass::ensure_space_for_methodids(int start_offset) {
1763   int new_jmeths = 0;
1764   int length = methods()->length();
1765   for (int index = start_offset; index < length; index++) {
1766     Method* m = methods()->at(index);
1767     jmethodID id = m->find_jmethod_id_or_null();
1768     if (id == NULL) {
1769       new_jmeths++;
1770     }
1771   }
1772   if (new_jmeths != 0) {
1773     Method::ensure_jmethod_ids(class_loader_data(), new_jmeths);
1774   }
1775 }
1776 
1777 // Common code to fetch the jmethodID from the cache or update the
1778 // cache with the new jmethodID. This function should never do anything
1779 // that causes the caller to go to a safepoint or we can deadlock with
1780 // the VMThread or have cache consistency issues.
1781 //
1782 jmethodID InstanceKlass::get_jmethod_id_fetch_or_update(
1783             size_t idnum, jmethodID new_id,
1784             jmethodID* new_jmeths, jmethodID* to_dealloc_id_p,
1785             jmethodID** to_dealloc_jmeths_p) {
1786   assert(new_id != NULL, "sanity check");
1787   assert(to_dealloc_id_p != NULL, "sanity check");
1788   assert(to_dealloc_jmeths_p != NULL, "sanity check");
1789   assert(Threads::number_of_threads() == 0 ||
1790          SafepointSynchronize::is_at_safepoint() ||
1791          JmethodIdCreation_lock->owned_by_self(), "sanity check");
1792 
1793   // reacquire the cache - we are locked, single threaded or at a safepoint
1794   jmethodID* jmeths = methods_jmethod_ids_acquire();
1795   jmethodID  id     = NULL;
1796   size_t     length = 0;
1797 
1798   if (jmeths == NULL ||                         // no cache yet
1799       (length = (size_t)jmeths[0]) <= idnum) {  // cache is too short
1800     if (jmeths != NULL) {
1801       // copy any existing entries from the old cache
1802       for (size_t index = 0; index < length; index++) {
1803         new_jmeths[index+1] = jmeths[index+1];
1804       }
1805       *to_dealloc_jmeths_p = jmeths;  // save old cache for later delete
1806     }
1807     release_set_methods_jmethod_ids(jmeths = new_jmeths);
1808   } else {
1809     // fetch jmethodID (if any) from the existing cache
1810     id = jmeths[idnum+1];
1811     *to_dealloc_jmeths_p = new_jmeths;  // save new cache for later delete
1812   }
1813   if (id == NULL) {
1814     // No matching jmethodID in the existing cache or we have a new
1815     // cache or we just grew the cache. This cache write is done here
1816     // by the first thread to win the foot race because a jmethodID
1817     // needs to be unique once it is generally available.
1818     id = new_id;
1819 
1820     // The jmethodID cache can be read while unlocked so we have to
1821     // make sure the new jmethodID is complete before installing it
1822     // in the cache.
1823     OrderAccess::release_store_ptr(&jmeths[idnum+1], id);
1824   } else {
1825     *to_dealloc_id_p = new_id; // save new id for later delete
1826   }
1827   return id;
1828 }
1829 
1830 
1831 // Common code to get the jmethodID cache length and the jmethodID
1832 // value at index idnum if there is one.
1833 //
1834 void InstanceKlass::get_jmethod_id_length_value(jmethodID* cache,
1835        size_t idnum, size_t *length_p, jmethodID* id_p) {
1836   assert(cache != NULL, "sanity check");
1837   assert(length_p != NULL, "sanity check");
1838   assert(id_p != NULL, "sanity check");
1839 
1840   // cache size is stored in element[0], other elements offset by one
1841   *length_p = (size_t)cache[0];
1842   if (*length_p <= idnum) {  // cache is too short
1843     *id_p = NULL;
1844   } else {
1845     *id_p = cache[idnum+1];  // fetch jmethodID (if any)
1846   }
1847 }
1848 
1849 
1850 // Lookup a jmethodID, NULL if not found.  Do no blocking, no allocations, no handles
1851 jmethodID InstanceKlass::jmethod_id_or_null(Method* method) {
1852   size_t idnum = (size_t)method->method_idnum();
1853   jmethodID* jmeths = methods_jmethod_ids_acquire();
1854   size_t length;                                // length assigned as debugging crumb
1855   jmethodID id = NULL;
1856   if (jmeths != NULL &&                         // If there is a cache
1857       (length = (size_t)jmeths[0]) > idnum) {   // and if it is long enough,
1858     id = jmeths[idnum+1];                       // Look up the id (may be NULL)
1859   }
1860   return id;
1861 }
1862 
1863 inline DependencyContext InstanceKlass::dependencies() {
1864   DependencyContext dep_context(&_dep_context);
1865   return dep_context;
1866 }
1867 
1868 int InstanceKlass::mark_dependent_nmethods(KlassDepChange& changes) {
1869   return dependencies().mark_dependent_nmethods(changes);
1870 }
1871 
1872 void InstanceKlass::add_dependent_nmethod(nmethod* nm) {
1873   dependencies().add_dependent_nmethod(nm);
1874 }
1875 
1876 void InstanceKlass::remove_dependent_nmethod(nmethod* nm, bool delete_immediately) {
1877   dependencies().remove_dependent_nmethod(nm, delete_immediately);
1878 }
1879 
1880 #ifndef PRODUCT
1881 void InstanceKlass::print_dependent_nmethods(bool verbose) {
1882   dependencies().print_dependent_nmethods(verbose);
1883 }
1884 
1885 bool InstanceKlass::is_dependent_nmethod(nmethod* nm) {
1886   return dependencies().is_dependent_nmethod(nm);
1887 }
1888 #endif //PRODUCT
1889 
1890 oop* InstanceKlass::klass_holder_addr() const   {
1891   return is_anonymous() ? const_cast<oop*>(&_java_mirror) : _class_loader_data->class_loader_addr();
1892 }
1893 
1894 void InstanceKlass::clean_weak_instanceklass_links(BoolObjectClosure* is_alive) {
1895   clean_implementors_list(is_alive);
1896   clean_method_data(is_alive);
1897 
1898   // Since GC iterates InstanceKlasses sequentially, it is safe to remove stale entries here.
1899   DependencyContext dep_context(&_dep_context);
1900   dep_context.expunge_stale_entries();
1901 }
1902 
1903 void InstanceKlass::clean_implementors_list(BoolObjectClosure* is_alive) {
1904   assert(class_loader_data()->is_alive(is_alive), "this klass should be live");
1905   if (is_interface()) {
1906     if (ClassUnloading) {
1907       Klass* impl = implementor();
1908       if (impl != NULL) {
1909         if (!impl->is_loader_alive(is_alive)) {
1910           // remove this guy
1911           Klass** klass = adr_implementor();
1912           assert(klass != NULL, "null klass");
1913           if (klass != NULL) {
1914             *klass = NULL;
1915           }
1916         }
1917       }
1918     }
1919   }
1920 }
1921 
1922 void InstanceKlass::clean_method_data(BoolObjectClosure* is_alive) {
1923   for (int m = 0; m < methods()->length(); m++) {
1924     MethodData* mdo = methods()->at(m)->method_data();
1925     if (mdo != NULL) {
1926       mdo->clean_method_data(is_alive);
1927     }
1928   }
1929 }
1930 
1931 bool InstanceKlass::supers_have_passed_fingerprint_checks() {
1932   if (java_super() != NULL && !java_super()->has_passed_fingerprint_check()) {
1933     ResourceMark rm;
1934     log_trace(class, fingerprint)("%s : super %s not fingerprinted", external_name(), java_super()->external_name());
1935     return false;
1936   }
1937 
1938   Array<Klass*>* local_interfaces = this->local_interfaces();
1939   if (local_interfaces != NULL) {
1940     int length = local_interfaces->length();
1941     for (int i = 0; i < length; i++) {
1942       InstanceKlass* intf = InstanceKlass::cast(local_interfaces->at(i));
1943       if (!intf->has_passed_fingerprint_check()) {
1944         ResourceMark rm;
1945         log_trace(class, fingerprint)("%s : interface %s not fingerprinted", external_name(), intf->external_name());
1946         return false;
1947       }
1948     }
1949   }
1950 
1951   return true;
1952 }
1953 
1954 bool InstanceKlass::should_store_fingerprint() {
1955 #if INCLUDE_AOT
1956   // We store the fingerprint into the InstanceKlass only in the following 2 cases:
1957   if (EnableJVMCI && !UseJVMCICompiler) {
1958     // (1) We are running AOT to generate a shared library.
1959     return true;
1960   }
1961   if (DumpSharedSpaces) {
1962     // (2) We are running -Xshare:dump to create a shared archive
1963     return true;
1964   }
1965 #endif
1966 
1967   // In all other cases we might set the _misc_has_passed_fingerprint_check bit,
1968   // but do not store the 64-bit fingerprint to save space.
1969   return false;
1970 }
1971 
1972 bool InstanceKlass::has_stored_fingerprint() const {
1973 #if INCLUDE_AOT
1974   return should_store_fingerprint() || is_shared();
1975 #else
1976   return false;
1977 #endif
1978 }
1979 
1980 uint64_t InstanceKlass::get_stored_fingerprint() const {
1981   address adr = adr_fingerprint();
1982   if (adr != NULL) {
1983     return (uint64_t)Bytes::get_native_u8(adr); // adr may not be 64-bit aligned
1984   }
1985   return 0;
1986 }
1987 
1988 void InstanceKlass::store_fingerprint(uint64_t fingerprint) {
1989   address adr = adr_fingerprint();
1990   if (adr != NULL) {
1991     Bytes::put_native_u8(adr, (u8)fingerprint); // adr may not be 64-bit aligned
1992 
1993     ResourceMark rm;
1994     log_trace(class, fingerprint)("stored as " PTR64_FORMAT " for class %s", fingerprint, external_name());
1995   }
1996 }
1997 
1998 static void remove_unshareable_in_class(Klass* k) {
1999   // remove klass's unshareable info
2000   k->remove_unshareable_info();
2001 }
2002 
2003 void InstanceKlass::remove_unshareable_info() {
2004   Klass::remove_unshareable_info();
2005   // Unlink the class
2006   if (is_linked()) {
2007     unlink_class();
2008   }
2009   init_implementor();
2010 
2011   constants()->remove_unshareable_info();
2012 
2013   assert(_dep_context == DependencyContext::EMPTY, "dependency context is not shareable");
2014 
2015   for (int i = 0; i < methods()->length(); i++) {
2016     Method* m = methods()->at(i);
2017     m->remove_unshareable_info();
2018   }
2019 
2020   // do array classes also.
2021   array_klasses_do(remove_unshareable_in_class);
2022 }
2023 
2024 static void restore_unshareable_in_class(Klass* k, TRAPS) {
2025   // Array classes have null protection domain.
2026   // --> see ArrayKlass::complete_create_array_klass()
2027   k->restore_unshareable_info(ClassLoaderData::the_null_class_loader_data(), Handle(), CHECK);
2028 }
2029 
2030 void InstanceKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
2031   set_package(loader_data, CHECK);
2032   Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
2033 
2034   Array<Method*>* methods = this->methods();
2035   int num_methods = methods->length();
2036   for (int index2 = 0; index2 < num_methods; ++index2) {
2037     methodHandle m(THREAD, methods->at(index2));
2038     m->restore_unshareable_info(CHECK);
2039   }
2040   if (JvmtiExport::has_redefined_a_class()) {
2041     // Reinitialize vtable because RedefineClasses may have changed some
2042     // entries in this vtable for super classes so the CDS vtable might
2043     // point to old or obsolete entries.  RedefineClasses doesn't fix up
2044     // vtables in the shared system dictionary, only the main one.
2045     // It also redefines the itable too so fix that too.
2046     ResourceMark rm(THREAD);
2047     vtable().initialize_vtable(false, CHECK);
2048     itable().initialize_itable(false, CHECK);
2049   }
2050 
2051   // restore constant pool resolved references
2052   constants()->restore_unshareable_info(CHECK);
2053 
2054   array_klasses_do(restore_unshareable_in_class, CHECK);
2055 }
2056 
2057 // returns true IFF is_in_error_state() has been changed as a result of this call.
2058 bool InstanceKlass::check_sharing_error_state() {
2059   assert(DumpSharedSpaces, "should only be called during dumping");
2060   bool old_state = is_in_error_state();
2061 
2062   if (!is_in_error_state()) {
2063     bool bad = false;
2064     for (InstanceKlass* sup = java_super(); sup; sup = sup->java_super()) {
2065       if (sup->is_in_error_state()) {
2066         bad = true;
2067         break;
2068       }
2069     }
2070     if (!bad) {
2071       Array<Klass*>* interfaces = transitive_interfaces();
2072       for (int i = 0; i < interfaces->length(); i++) {
2073         Klass* iface = interfaces->at(i);
2074         if (InstanceKlass::cast(iface)->is_in_error_state()) {
2075           bad = true;
2076           break;
2077         }
2078       }
2079     }
2080 
2081     if (bad) {
2082       set_in_error_state();
2083     }
2084   }
2085 
2086   return (old_state != is_in_error_state());
2087 }
2088 
2089 #if INCLUDE_JVMTI
2090 static void clear_all_breakpoints(Method* m) {
2091   m->clear_all_breakpoints();
2092 }
2093 #endif
2094 
2095 void InstanceKlass::notify_unload_class(InstanceKlass* ik) {
2096   // notify the debugger
2097   if (JvmtiExport::should_post_class_unload()) {
2098     JvmtiExport::post_class_unload(ik);
2099   }
2100 
2101   // notify ClassLoadingService of class unload
2102   ClassLoadingService::notify_class_unloaded(ik);
2103 }
2104 
2105 void InstanceKlass::release_C_heap_structures(InstanceKlass* ik) {
2106   // Clean up C heap
2107   ik->release_C_heap_structures();
2108   ik->constants()->release_C_heap_structures();
2109 }
2110 
2111 void InstanceKlass::release_C_heap_structures() {
2112   // Can't release the constant pool here because the constant pool can be
2113   // deallocated separately from the InstanceKlass for default methods and
2114   // redefine classes.
2115 
2116   // Deallocate oop map cache
2117   if (_oop_map_cache != NULL) {
2118     delete _oop_map_cache;
2119     _oop_map_cache = NULL;
2120   }
2121 
2122   // Deallocate JNI identifiers for jfieldIDs
2123   JNIid::deallocate(jni_ids());
2124   set_jni_ids(NULL);
2125 
2126   jmethodID* jmeths = methods_jmethod_ids_acquire();
2127   if (jmeths != (jmethodID*)NULL) {
2128     release_set_methods_jmethod_ids(NULL);
2129     FreeHeap(jmeths);
2130   }
2131 
2132   // Deallocate MemberNameTable
2133   {
2134     Mutex* lock_or_null = SafepointSynchronize::is_at_safepoint() ? NULL : MemberNameTable_lock;
2135     MutexLockerEx ml(lock_or_null, Mutex::_no_safepoint_check_flag);
2136     MemberNameTable* mnt = member_names();
2137     if (mnt != NULL) {
2138       delete mnt;
2139       set_member_names(NULL);
2140     }
2141   }
2142 
2143   // Release dependencies.
2144   // It is desirable to use DC::remove_all_dependents() here, but, unfortunately,
2145   // it is not safe (see JDK-8143408). The problem is that the klass dependency
2146   // context can contain live dependencies, since there's a race between nmethod &
2147   // klass unloading. If the klass is dead when nmethod unloading happens, relevant
2148   // dependencies aren't removed from the context associated with the class (see
2149   // nmethod::flush_dependencies). It ends up during klass unloading as seemingly
2150   // live dependencies pointing to unloaded nmethods and causes a crash in
2151   // DC::remove_all_dependents() when it touches unloaded nmethod.
2152   dependencies().wipe();
2153 
2154 #if INCLUDE_JVMTI
2155   // Deallocate breakpoint records
2156   if (breakpoints() != 0x0) {
2157     methods_do(clear_all_breakpoints);
2158     assert(breakpoints() == 0x0, "should have cleared breakpoints");
2159   }
2160 
2161   // deallocate the cached class file
2162   if (_cached_class_file != NULL && !MetaspaceShared::is_in_shared_space(_cached_class_file)) {
2163     os::free(_cached_class_file);
2164     _cached_class_file = NULL;
2165   }
2166 #endif
2167 
2168   // Decrement symbol reference counts associated with the unloaded class.
2169   if (_name != NULL) _name->decrement_refcount();
2170   // unreference array name derived from this class name (arrays of an unloaded
2171   // class can't be referenced anymore).
2172   if (_array_name != NULL)  _array_name->decrement_refcount();
2173   if (_source_debug_extension != NULL) FREE_C_HEAP_ARRAY(char, _source_debug_extension);
2174 
2175   assert(_total_instanceKlass_count >= 1, "Sanity check");
2176   Atomic::dec(&_total_instanceKlass_count);
2177 }
2178 
2179 void InstanceKlass::set_source_debug_extension(const char* array, int length) {
2180   if (array == NULL) {
2181     _source_debug_extension = NULL;
2182   } else {
2183     // Adding one to the attribute length in order to store a null terminator
2184     // character could cause an overflow because the attribute length is
2185     // already coded with an u4 in the classfile, but in practice, it's
2186     // unlikely to happen.
2187     assert((length+1) > length, "Overflow checking");
2188     char* sde = NEW_C_HEAP_ARRAY(char, (length + 1), mtClass);
2189     for (int i = 0; i < length; i++) {
2190       sde[i] = array[i];
2191     }
2192     sde[length] = '\0';
2193     _source_debug_extension = sde;
2194   }
2195 }
2196 
2197 address InstanceKlass::static_field_addr(int offset) {
2198   return (address)(offset + InstanceMirrorKlass::offset_of_static_fields() + cast_from_oop<intptr_t>(java_mirror()));
2199 }
2200 
2201 
2202 const char* InstanceKlass::signature_name() const {
2203   int hash_len = 0;
2204   char hash_buf[40];
2205 
2206   // If this is an anonymous class, append a hash to make the name unique
2207   if (is_anonymous()) {
2208     intptr_t hash = (java_mirror() != NULL) ? java_mirror()->identity_hash() : 0;
2209     jio_snprintf(hash_buf, sizeof(hash_buf), "/" UINTX_FORMAT, (uintx)hash);
2210     hash_len = (int)strlen(hash_buf);
2211   }
2212 
2213   // Get the internal name as a c string
2214   const char* src = (const char*) (name()->as_C_string());
2215   const int src_length = (int)strlen(src);
2216 
2217   char* dest = NEW_RESOURCE_ARRAY(char, src_length + hash_len + 3);
2218 
2219   // Add L as type indicator
2220   int dest_index = 0;
2221   dest[dest_index++] = 'L';
2222 
2223   // Add the actual class name
2224   for (int src_index = 0; src_index < src_length; ) {
2225     dest[dest_index++] = src[src_index++];
2226   }
2227 
2228   // If we have a hash, append it
2229   for (int hash_index = 0; hash_index < hash_len; ) {
2230     dest[dest_index++] = hash_buf[hash_index++];
2231   }
2232 
2233   // Add the semicolon and the NULL
2234   dest[dest_index++] = ';';
2235   dest[dest_index] = '\0';
2236   return dest;
2237 }
2238 
2239 // Used to obtain the package name from a fully qualified class name.
2240 Symbol* InstanceKlass::package_from_name(const Symbol* name, TRAPS) {
2241   if (name == NULL) {
2242     return NULL;
2243   } else {
2244     if (name->utf8_length() <= 0) {
2245       return NULL;
2246     }
2247     ResourceMark rm;
2248     const char* package_name = ClassLoader::package_from_name((const char*) name->as_C_string());
2249     if (package_name == NULL) {
2250       return NULL;
2251     }
2252     Symbol* pkg_name = SymbolTable::new_symbol(package_name, THREAD);
2253     return pkg_name;
2254   }
2255 }
2256 
2257 ModuleEntry* InstanceKlass::module() const {
2258   if (!in_unnamed_package()) {
2259     return _package_entry->module();
2260   }
2261   const Klass* host = host_klass();
2262   if (host == NULL) {
2263     return class_loader_data()->unnamed_module();
2264   }
2265   return host->class_loader_data()->unnamed_module();
2266 }
2267 
2268 void InstanceKlass::set_package(ClassLoaderData* loader_data, TRAPS) {
2269 
2270   // ensure java/ packages only loaded by boot or platform builtin loaders
2271   Handle class_loader(THREAD, loader_data->class_loader());
2272   check_prohibited_package(name(), class_loader, CHECK);
2273 
2274   TempNewSymbol pkg_name = package_from_name(name(), CHECK);
2275 
2276   if (pkg_name != NULL && loader_data != NULL) {
2277 
2278     // Find in class loader's package entry table.
2279     _package_entry = loader_data->packages()->lookup_only(pkg_name);
2280 
2281     // If the package name is not found in the loader's package
2282     // entry table, it is an indication that the package has not
2283     // been defined. Consider it defined within the unnamed module.
2284     if (_package_entry == NULL) {
2285       ResourceMark rm;
2286 
2287       if (!ModuleEntryTable::javabase_defined()) {
2288         // Before java.base is defined during bootstrapping, define all packages in
2289         // the java.base module.  If a non-java.base package is erroneously placed
2290         // in the java.base module it will be caught later when java.base
2291         // is defined by ModuleEntryTable::verify_javabase_packages check.
2292         assert(ModuleEntryTable::javabase_moduleEntry() != NULL, JAVA_BASE_NAME " module is NULL");
2293         _package_entry = loader_data->packages()->lookup(pkg_name, ModuleEntryTable::javabase_moduleEntry());
2294       } else {
2295         assert(loader_data->unnamed_module() != NULL, "unnamed module is NULL");
2296         _package_entry = loader_data->packages()->lookup(pkg_name,
2297                                                          loader_data->unnamed_module());
2298       }
2299 
2300       // A package should have been successfully created
2301       assert(_package_entry != NULL, "Package entry for class %s not found, loader %s",
2302              name()->as_C_string(), loader_data->loader_name());
2303     }
2304 
2305     if (log_is_enabled(Debug, modules)) {
2306       ResourceMark rm;
2307       ModuleEntry* m = _package_entry->module();
2308       log_trace(modules)("Setting package: class: %s, package: %s, loader: %s, module: %s",
2309                          external_name(),
2310                          pkg_name->as_C_string(),
2311                          loader_data->loader_name(),
2312                          (m->is_named() ? m->name()->as_C_string() : UNNAMED_MODULE));
2313     }
2314   } else {
2315     ResourceMark rm;
2316     log_trace(modules)("Setting package: class: %s, package: unnamed, loader: %s, module: %s",
2317                        external_name(),
2318                        (loader_data != NULL) ? loader_data->loader_name() : "NULL",
2319                        UNNAMED_MODULE);
2320   }
2321 }
2322 
2323 
2324 // different versions of is_same_class_package
2325 
2326 bool InstanceKlass::is_same_class_package(const Klass* class2) const {
2327   oop classloader1 = this->class_loader();
2328   PackageEntry* classpkg1 = this->package();
2329   if (class2->is_objArray_klass()) {
2330     class2 = ObjArrayKlass::cast(class2)->bottom_klass();
2331   }
2332 
2333   oop classloader2;
2334   PackageEntry* classpkg2;
2335   if (class2->is_instance_klass()) {
2336     classloader2 = class2->class_loader();
2337     classpkg2 = class2->package();
2338   } else {
2339     assert(class2->is_typeArray_klass(), "should be type array");
2340     classloader2 = NULL;
2341     classpkg2 = NULL;
2342   }
2343 
2344   // Same package is determined by comparing class loader
2345   // and package entries. Both must be the same. This rule
2346   // applies even to classes that are defined in the unnamed
2347   // package, they still must have the same class loader.
2348   if ((classloader1 == classloader2) && (classpkg1 == classpkg2)) {
2349     return true;
2350   }
2351 
2352   return false;
2353 }
2354 
2355 bool InstanceKlass::is_same_class_package(oop other_class_loader,
2356                                           const Symbol* other_class_name) const {
2357   oop this_class_loader = class_loader();
2358   const Symbol* const this_class_name = name();
2359 
2360   return InstanceKlass::is_same_class_package(this_class_loader,
2361                                              this_class_name,
2362                                              other_class_loader,
2363                                              other_class_name);
2364 }
2365 
2366 // return true if two classes are in the same package, classloader
2367 // and classname information is enough to determine a class's package
2368 bool InstanceKlass::is_same_class_package(oop class_loader1, const Symbol* class_name1,
2369                                           oop class_loader2, const Symbol* class_name2) {
2370   if (class_loader1 != class_loader2) {
2371     return false;
2372   } else if (class_name1 == class_name2) {
2373     return true;
2374   } else {
2375     ResourceMark rm;
2376 
2377     bool bad_class_name = false;
2378     const char* name1 = ClassLoader::package_from_name((const char*) class_name1->as_C_string(), &bad_class_name);
2379     if (bad_class_name) {
2380       return false;
2381     }
2382 
2383     const char* name2 = ClassLoader::package_from_name((const char*) class_name2->as_C_string(), &bad_class_name);
2384     if (bad_class_name) {
2385       return false;
2386     }
2387 
2388     if ((name1 == NULL) || (name2 == NULL)) {
2389       // One of the two doesn't have a package.  Only return true
2390       // if the other one also doesn't have a package.
2391       return name1 == name2;
2392     }
2393 
2394     // Check that package is identical
2395     return (strcmp(name1, name2) == 0);
2396   }
2397 }
2398 
2399 // Returns true iff super_method can be overridden by a method in targetclassname
2400 // See JLS 3rd edition 8.4.6.1
2401 // Assumes name-signature match
2402 // "this" is InstanceKlass of super_method which must exist
2403 // note that the InstanceKlass of the method in the targetclassname has not always been created yet
2404 bool InstanceKlass::is_override(const methodHandle& super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS) {
2405    // Private methods can not be overridden
2406    if (super_method->is_private()) {
2407      return false;
2408    }
2409    // If super method is accessible, then override
2410    if ((super_method->is_protected()) ||
2411        (super_method->is_public())) {
2412      return true;
2413    }
2414    // Package-private methods are not inherited outside of package
2415    assert(super_method->is_package_private(), "must be package private");
2416    return(is_same_class_package(targetclassloader(), targetclassname));
2417 }
2418 
2419 // Only boot and platform class loaders can define classes in "java/" packages.
2420 void InstanceKlass::check_prohibited_package(Symbol* class_name,
2421                                              Handle class_loader,
2422                                              TRAPS) {
2423   if (!class_loader.is_null() &&
2424       !SystemDictionary::is_platform_class_loader(class_loader()) &&
2425       class_name != NULL) {
2426     ResourceMark rm(THREAD);
2427     char* name = class_name->as_C_string();
2428     if (strncmp(name, JAVAPKG, JAVAPKG_LEN) == 0 && name[JAVAPKG_LEN] == '/') {
2429       TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK);
2430       assert(pkg_name != NULL, "Error in parsing package name starting with 'java/'");
2431       name = pkg_name->as_C_string();
2432       const char* class_loader_name = SystemDictionary::loader_name(class_loader());
2433       StringUtils::replace_no_expand(name, "/", ".");
2434       const char* msg_text1 = "Class loader (instance of): ";
2435       const char* msg_text2 = " tried to load prohibited package name: ";
2436       size_t len = strlen(msg_text1) + strlen(class_loader_name) + strlen(msg_text2) + strlen(name) + 1;
2437       char* message = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len);
2438       jio_snprintf(message, len, "%s%s%s%s", msg_text1, class_loader_name, msg_text2, name);
2439       THROW_MSG(vmSymbols::java_lang_SecurityException(), message);
2440     }
2441   }
2442   return;
2443 }
2444 
2445 // tell if two classes have the same enclosing class (at package level)
2446 bool InstanceKlass::is_same_package_member(const Klass* class2, TRAPS) const {
2447   if (class2 == this) return true;
2448   if (!class2->is_instance_klass())  return false;
2449 
2450   // must be in same package before we try anything else
2451   if (!is_same_class_package(class2))
2452     return false;
2453 
2454   // As long as there is an outer_this.getEnclosingClass,
2455   // shift the search outward.
2456   const InstanceKlass* outer_this = this;
2457   for (;;) {
2458     // As we walk along, look for equalities between outer_this and class2.
2459     // Eventually, the walks will terminate as outer_this stops
2460     // at the top-level class around the original class.
2461     bool ignore_inner_is_member;
2462     const Klass* next = outer_this->compute_enclosing_class(&ignore_inner_is_member,
2463                                                             CHECK_false);
2464     if (next == NULL)  break;
2465     if (next == class2)  return true;
2466     outer_this = InstanceKlass::cast(next);
2467   }
2468 
2469   // Now do the same for class2.
2470   const InstanceKlass* outer2 = InstanceKlass::cast(class2);
2471   for (;;) {
2472     bool ignore_inner_is_member;
2473     Klass* next = outer2->compute_enclosing_class(&ignore_inner_is_member,
2474                                                     CHECK_false);
2475     if (next == NULL)  break;
2476     // Might as well check the new outer against all available values.
2477     if (next == this)  return true;
2478     if (next == outer_this)  return true;
2479     outer2 = InstanceKlass::cast(next);
2480   }
2481 
2482   // If by this point we have not found an equality between the
2483   // two classes, we know they are in separate package members.
2484   return false;
2485 }
2486 
2487 bool InstanceKlass::find_inner_classes_attr(int* ooff, int* noff, TRAPS) const {
2488   constantPoolHandle i_cp(THREAD, constants());
2489   for (InnerClassesIterator iter(this); !iter.done(); iter.next()) {
2490     int ioff = iter.inner_class_info_index();
2491     if (ioff != 0) {
2492       // Check to see if the name matches the class we're looking for
2493       // before attempting to find the class.
2494       if (i_cp->klass_name_at_matches(this, ioff)) {
2495         Klass* inner_klass = i_cp->klass_at(ioff, CHECK_false);
2496         if (this == inner_klass) {
2497           *ooff = iter.outer_class_info_index();
2498           *noff = iter.inner_name_index();
2499           return true;
2500         }
2501       }
2502     }
2503   }
2504   return false;
2505 }
2506 
2507 InstanceKlass* InstanceKlass::compute_enclosing_class(bool* inner_is_member, TRAPS) const {
2508   InstanceKlass* outer_klass = NULL;
2509   *inner_is_member = false;
2510   int ooff = 0, noff = 0;
2511   bool has_inner_classes_attr = find_inner_classes_attr(&ooff, &noff, THREAD);
2512   if (has_inner_classes_attr) {
2513     constantPoolHandle i_cp(THREAD, constants());
2514     if (ooff != 0) {
2515       Klass* ok = i_cp->klass_at(ooff, CHECK_NULL);
2516       outer_klass = InstanceKlass::cast(ok);
2517       *inner_is_member = true;
2518     }
2519     if (NULL == outer_klass) {
2520       // It may be anonymous; try for that.
2521       int encl_method_class_idx = enclosing_method_class_index();
2522       if (encl_method_class_idx != 0) {
2523         Klass* ok = i_cp->klass_at(encl_method_class_idx, CHECK_NULL);
2524         outer_klass = InstanceKlass::cast(ok);
2525         *inner_is_member = false;
2526       }
2527     }
2528   }
2529 
2530   // If no inner class attribute found for this class.
2531   if (NULL == outer_klass) return NULL;
2532 
2533   // Throws an exception if outer klass has not declared k as an inner klass
2534   // We need evidence that each klass knows about the other, or else
2535   // the system could allow a spoof of an inner class to gain access rights.
2536   Reflection::check_for_inner_class(outer_klass, this, *inner_is_member, CHECK_NULL);
2537   return outer_klass;
2538 }
2539 
2540 jint InstanceKlass::compute_modifier_flags(TRAPS) const {
2541   jint access = access_flags().as_int();
2542 
2543   // But check if it happens to be member class.
2544   InnerClassesIterator iter(this);
2545   for (; !iter.done(); iter.next()) {
2546     int ioff = iter.inner_class_info_index();
2547     // Inner class attribute can be zero, skip it.
2548     // Strange but true:  JVM spec. allows null inner class refs.
2549     if (ioff == 0) continue;
2550 
2551     // only look at classes that are already loaded
2552     // since we are looking for the flags for our self.
2553     Symbol* inner_name = constants()->klass_name_at(ioff);
2554     if (name() == inner_name) {
2555       // This is really a member class.
2556       access = iter.inner_access_flags();
2557       break;
2558     }
2559   }
2560   // Remember to strip ACC_SUPER bit
2561   return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
2562 }
2563 
2564 jint InstanceKlass::jvmti_class_status() const {
2565   jint result = 0;
2566 
2567   if (is_linked()) {
2568     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
2569   }
2570 
2571   if (is_initialized()) {
2572     assert(is_linked(), "Class status is not consistent");
2573     result |= JVMTI_CLASS_STATUS_INITIALIZED;
2574   }
2575   if (is_in_error_state()) {
2576     result |= JVMTI_CLASS_STATUS_ERROR;
2577   }
2578   return result;
2579 }
2580 
2581 Method* InstanceKlass::method_at_itable(Klass* holder, int index, TRAPS) {
2582   itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
2583   int method_table_offset_in_words = ioe->offset()/wordSize;
2584   int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())
2585                        / itableOffsetEntry::size();
2586 
2587   for (int cnt = 0 ; ; cnt ++, ioe ++) {
2588     // If the interface isn't implemented by the receiver class,
2589     // the VM should throw IncompatibleClassChangeError.
2590     if (cnt >= nof_interfaces) {
2591       THROW_NULL(vmSymbols::java_lang_IncompatibleClassChangeError());
2592     }
2593 
2594     Klass* ik = ioe->interface_klass();
2595     if (ik == holder) break;
2596   }
2597 
2598   itableMethodEntry* ime = ioe->first_method_entry(this);
2599   Method* m = ime[index].method();
2600   if (m == NULL) {
2601     THROW_NULL(vmSymbols::java_lang_AbstractMethodError());
2602   }
2603   return m;
2604 }
2605 
2606 
2607 #if INCLUDE_JVMTI
2608 // update default_methods for redefineclasses for methods that are
2609 // not yet in the vtable due to concurrent subclass define and superinterface
2610 // redefinition
2611 // Note: those in the vtable, should have been updated via adjust_method_entries
2612 void InstanceKlass::adjust_default_methods(InstanceKlass* holder, bool* trace_name_printed) {
2613   // search the default_methods for uses of either obsolete or EMCP methods
2614   if (default_methods() != NULL) {
2615     for (int index = 0; index < default_methods()->length(); index ++) {
2616       Method* old_method = default_methods()->at(index);
2617       if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
2618         continue; // skip uninteresting entries
2619       }
2620       assert(!old_method->is_deleted(), "default methods may not be deleted");
2621 
2622       Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
2623 
2624       assert(new_method != NULL, "method_with_idnum() should not be NULL");
2625       assert(old_method != new_method, "sanity check");
2626 
2627       default_methods()->at_put(index, new_method);
2628       if (log_is_enabled(Info, redefine, class, update)) {
2629         ResourceMark rm;
2630         if (!(*trace_name_printed)) {
2631           log_info(redefine, class, update)
2632             ("adjust: klassname=%s default methods from name=%s",
2633              external_name(), old_method->method_holder()->external_name());
2634           *trace_name_printed = true;
2635         }
2636         log_debug(redefine, class, update, vtables)
2637           ("default method update: %s(%s) ",
2638            new_method->name()->as_C_string(), new_method->signature()->as_C_string());
2639       }
2640     }
2641   }
2642 }
2643 #endif // INCLUDE_JVMTI
2644 
2645 // On-stack replacement stuff
2646 void InstanceKlass::add_osr_nmethod(nmethod* n) {
2647   // only one compilation can be active
2648   {
2649     // This is a short non-blocking critical region, so the no safepoint check is ok.
2650     MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
2651     assert(n->is_osr_method(), "wrong kind of nmethod");
2652     n->set_osr_link(osr_nmethods_head());
2653     set_osr_nmethods_head(n);
2654     // Raise the highest osr level if necessary
2655     if (TieredCompilation) {
2656       Method* m = n->method();
2657       m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
2658     }
2659   }
2660 
2661   // Get rid of the osr methods for the same bci that have lower levels.
2662   if (TieredCompilation) {
2663     for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
2664       nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
2665       if (inv != NULL && inv->is_in_use()) {
2666         inv->make_not_entrant();
2667       }
2668     }
2669   }
2670 }
2671 
2672 // Remove osr nmethod from the list. Return true if found and removed.
2673 bool InstanceKlass::remove_osr_nmethod(nmethod* n) {
2674   // This is a short non-blocking critical region, so the no safepoint check is ok.
2675   MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
2676   assert(n->is_osr_method(), "wrong kind of nmethod");
2677   nmethod* last = NULL;
2678   nmethod* cur  = osr_nmethods_head();
2679   int max_level = CompLevel_none;  // Find the max comp level excluding n
2680   Method* m = n->method();
2681   // Search for match
2682   bool found = false;
2683   while(cur != NULL && cur != n) {
2684     if (TieredCompilation && m == cur->method()) {
2685       // Find max level before n
2686       max_level = MAX2(max_level, cur->comp_level());
2687     }
2688     last = cur;
2689     cur = cur->osr_link();
2690   }
2691   nmethod* next = NULL;
2692   if (cur == n) {
2693     found = true;
2694     next = cur->osr_link();
2695     if (last == NULL) {
2696       // Remove first element
2697       set_osr_nmethods_head(next);
2698     } else {
2699       last->set_osr_link(next);
2700     }
2701   }
2702   n->set_osr_link(NULL);
2703   if (TieredCompilation) {
2704     cur = next;
2705     while (cur != NULL) {
2706       // Find max level after n
2707       if (m == cur->method()) {
2708         max_level = MAX2(max_level, cur->comp_level());
2709       }
2710       cur = cur->osr_link();
2711     }
2712     m->set_highest_osr_comp_level(max_level);
2713   }
2714   return found;
2715 }
2716 
2717 int InstanceKlass::mark_osr_nmethods(const Method* m) {
2718   // This is a short non-blocking critical region, so the no safepoint check is ok.
2719   MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
2720   nmethod* osr = osr_nmethods_head();
2721   int found = 0;
2722   while (osr != NULL) {
2723     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
2724     if (osr->method() == m) {
2725       osr->mark_for_deoptimization();
2726       found++;
2727     }
2728     osr = osr->osr_link();
2729   }
2730   return found;
2731 }
2732 
2733 nmethod* InstanceKlass::lookup_osr_nmethod(const Method* m, int bci, int comp_level, bool match_level) const {
2734   // This is a short non-blocking critical region, so the no safepoint check is ok.
2735   MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
2736   nmethod* osr = osr_nmethods_head();
2737   nmethod* best = NULL;
2738   while (osr != NULL) {
2739     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
2740     // There can be a time when a c1 osr method exists but we are waiting
2741     // for a c2 version. When c2 completes its osr nmethod we will trash
2742     // the c1 version and only be able to find the c2 version. However
2743     // while we overflow in the c1 code at back branches we don't want to
2744     // try and switch to the same code as we are already running
2745 
2746     if (osr->method() == m &&
2747         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
2748       if (match_level) {
2749         if (osr->comp_level() == comp_level) {
2750           // Found a match - return it.
2751           return osr;
2752         }
2753       } else {
2754         if (best == NULL || (osr->comp_level() > best->comp_level())) {
2755           if (osr->comp_level() == CompLevel_highest_tier) {
2756             // Found the best possible - return it.
2757             return osr;
2758           }
2759           best = osr;
2760         }
2761       }
2762     }
2763     osr = osr->osr_link();
2764   }
2765   if (best != NULL && best->comp_level() >= comp_level && match_level == false) {
2766     return best;
2767   }
2768   return NULL;
2769 }
2770 
2771 oop InstanceKlass::add_member_name(Handle mem_name, bool intern) {
2772   jweak mem_name_wref = JNIHandles::make_weak_global(mem_name);
2773   MutexLocker ml(MemberNameTable_lock);
2774   DEBUG_ONLY(NoSafepointVerifier nsv);
2775 
2776   // Check if method has been redefined while taking out MemberNameTable_lock, if so
2777   // return false.  We cannot cache obsolete methods. They will crash when the function
2778   // is called!
2779   Method* method = (Method*)java_lang_invoke_MemberName::vmtarget(mem_name());
2780   if (method->is_obsolete()) {
2781     return NULL;
2782   } else if (method->is_old()) {
2783     // Replace method with redefined version
2784     java_lang_invoke_MemberName::set_vmtarget(mem_name(), method_with_idnum(method->method_idnum()));
2785   }
2786 
2787   if (_member_names == NULL) {
2788     _member_names = new (ResourceObj::C_HEAP, mtClass) MemberNameTable(idnum_allocated_count());
2789   }
2790   if (intern) {
2791     return _member_names->find_or_add_member_name(mem_name_wref);
2792   } else {
2793     return _member_names->add_member_name(mem_name_wref);
2794   }
2795 }
2796 
2797 // -----------------------------------------------------------------------------------------------------
2798 // Printing
2799 
2800 #ifndef PRODUCT
2801 
2802 #define BULLET  " - "
2803 
2804 static const char* state_names[] = {
2805   "allocated", "loaded", "linked", "being_initialized", "fully_initialized", "initialization_error"
2806 };
2807 
2808 static void print_vtable(intptr_t* start, int len, outputStream* st) {
2809   for (int i = 0; i < len; i++) {
2810     intptr_t e = start[i];
2811     st->print("%d : " INTPTR_FORMAT, i, e);
2812     if (e != 0 && ((Metadata*)e)->is_metaspace_object()) {
2813       st->print(" ");
2814       ((Metadata*)e)->print_value_on(st);
2815     }
2816     st->cr();
2817   }
2818 }
2819 
2820 static void print_vtable(vtableEntry* start, int len, outputStream* st) {
2821   return print_vtable(reinterpret_cast<intptr_t*>(start), len, st);
2822 }
2823 
2824 void InstanceKlass::print_on(outputStream* st) const {
2825   assert(is_klass(), "must be klass");
2826   Klass::print_on(st);
2827 
2828   st->print(BULLET"instance size:     %d", size_helper());                        st->cr();
2829   st->print(BULLET"klass size:        %d", size());                               st->cr();
2830   st->print(BULLET"access:            "); access_flags().print_on(st);            st->cr();
2831   st->print(BULLET"state:             "); st->print_cr("%s", state_names[_init_state]);
2832   st->print(BULLET"name:              "); name()->print_value_on(st);             st->cr();
2833   st->print(BULLET"super:             "); super()->print_value_on_maybe_null(st); st->cr();
2834   st->print(BULLET"sub:               ");
2835   Klass* sub = subklass();
2836   int n;
2837   for (n = 0; sub != NULL; n++, sub = sub->next_sibling()) {
2838     if (n < MaxSubklassPrintSize) {
2839       sub->print_value_on(st);
2840       st->print("   ");
2841     }
2842   }
2843   if (n >= MaxSubklassPrintSize) st->print("(" INTX_FORMAT " more klasses...)", n - MaxSubklassPrintSize);
2844   st->cr();
2845 
2846   if (is_interface()) {
2847     st->print_cr(BULLET"nof implementors:  %d", nof_implementors());
2848     if (nof_implementors() == 1) {
2849       st->print_cr(BULLET"implementor:    ");
2850       st->print("   ");
2851       implementor()->print_value_on(st);
2852       st->cr();
2853     }
2854   }
2855 
2856   st->print(BULLET"arrays:            "); array_klasses()->print_value_on_maybe_null(st); st->cr();
2857   st->print(BULLET"methods:           "); methods()->print_value_on(st);                  st->cr();
2858   if (Verbose || WizardMode) {
2859     Array<Method*>* method_array = methods();
2860     for (int i = 0; i < method_array->length(); i++) {
2861       st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
2862     }
2863   }
2864   st->print(BULLET"method ordering:   "); method_ordering()->print_value_on(st);      st->cr();
2865   st->print(BULLET"default_methods:   "); default_methods()->print_value_on(st);      st->cr();
2866   if (Verbose && default_methods() != NULL) {
2867     Array<Method*>* method_array = default_methods();
2868     for (int i = 0; i < method_array->length(); i++) {
2869       st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
2870     }
2871   }
2872   if (default_vtable_indices() != NULL) {
2873     st->print(BULLET"default vtable indices:   "); default_vtable_indices()->print_value_on(st);       st->cr();
2874   }
2875   st->print(BULLET"local interfaces:  "); local_interfaces()->print_value_on(st);      st->cr();
2876   st->print(BULLET"trans. interfaces: "); transitive_interfaces()->print_value_on(st); st->cr();
2877   st->print(BULLET"constants:         "); constants()->print_value_on(st);         st->cr();
2878   if (class_loader_data() != NULL) {
2879     st->print(BULLET"class loader data:  ");
2880     class_loader_data()->print_value_on(st);
2881     st->cr();
2882   }
2883   st->print(BULLET"host class:        "); host_klass()->print_value_on_maybe_null(st); st->cr();
2884   if (source_file_name() != NULL) {
2885     st->print(BULLET"source file:       ");
2886     source_file_name()->print_value_on(st);
2887     st->cr();
2888   }
2889   if (source_debug_extension() != NULL) {
2890     st->print(BULLET"source debug extension:       ");
2891     st->print("%s", source_debug_extension());
2892     st->cr();
2893   }
2894   st->print(BULLET"class annotations:       "); class_annotations()->print_value_on(st); st->cr();
2895   st->print(BULLET"class type annotations:  "); class_type_annotations()->print_value_on(st); st->cr();
2896   st->print(BULLET"field annotations:       "); fields_annotations()->print_value_on(st); st->cr();
2897   st->print(BULLET"field type annotations:  "); fields_type_annotations()->print_value_on(st); st->cr();
2898   {
2899     bool have_pv = false;
2900     // previous versions are linked together through the InstanceKlass
2901     for (InstanceKlass* pv_node = previous_versions();
2902          pv_node != NULL;
2903          pv_node = pv_node->previous_versions()) {
2904       if (!have_pv)
2905         st->print(BULLET"previous version:  ");
2906       have_pv = true;
2907       pv_node->constants()->print_value_on(st);
2908     }
2909     if (have_pv) st->cr();
2910   }
2911 
2912   if (generic_signature() != NULL) {
2913     st->print(BULLET"generic signature: ");
2914     generic_signature()->print_value_on(st);
2915     st->cr();
2916   }
2917   st->print(BULLET"inner classes:     "); inner_classes()->print_value_on(st);     st->cr();
2918   st->print(BULLET"java mirror:       "); java_mirror()->print_value_on(st);       st->cr();
2919   st->print(BULLET"vtable length      %d  (start addr: " INTPTR_FORMAT ")", vtable_length(), p2i(start_of_vtable())); st->cr();
2920   if (vtable_length() > 0 && (Verbose || WizardMode))  print_vtable(start_of_vtable(), vtable_length(), st);
2921   st->print(BULLET"itable length      %d (start addr: " INTPTR_FORMAT ")", itable_length(), p2i(start_of_itable())); st->cr();
2922   if (itable_length() > 0 && (Verbose || WizardMode))  print_vtable(start_of_itable(), itable_length(), st);
2923   st->print_cr(BULLET"---- static fields (%d words):", static_field_size());
2924   FieldPrinter print_static_field(st);
2925   ((InstanceKlass*)this)->do_local_static_fields(&print_static_field);
2926   st->print_cr(BULLET"---- non-static fields (%d words):", nonstatic_field_size());
2927   FieldPrinter print_nonstatic_field(st);
2928   InstanceKlass* ik = const_cast<InstanceKlass*>(this);
2929   ik->do_nonstatic_fields(&print_nonstatic_field);
2930 
2931   st->print(BULLET"non-static oop maps: ");
2932   OopMapBlock* map     = start_of_nonstatic_oop_maps();
2933   OopMapBlock* end_map = map + nonstatic_oop_map_count();
2934   while (map < end_map) {
2935     st->print("%d-%d ", map->offset(), map->offset() + heapOopSize*(map->count() - 1));
2936     map++;
2937   }
2938   st->cr();
2939 }
2940 
2941 #endif //PRODUCT
2942 
2943 void InstanceKlass::print_value_on(outputStream* st) const {
2944   assert(is_klass(), "must be klass");
2945   if (Verbose || WizardMode)  access_flags().print_on(st);
2946   name()->print_value_on(st);
2947 }
2948 
2949 #ifndef PRODUCT
2950 
2951 void FieldPrinter::do_field(fieldDescriptor* fd) {
2952   _st->print(BULLET);
2953    if (_obj == NULL) {
2954      fd->print_on(_st);
2955      _st->cr();
2956    } else {
2957      fd->print_on_for(_st, _obj);
2958      _st->cr();
2959    }
2960 }
2961 
2962 
2963 void InstanceKlass::oop_print_on(oop obj, outputStream* st) {
2964   Klass::oop_print_on(obj, st);
2965 
2966   if (this == SystemDictionary::String_klass()) {
2967     typeArrayOop value  = java_lang_String::value(obj);
2968     juint        length = java_lang_String::length(obj);
2969     if (value != NULL &&
2970         value->is_typeArray() &&
2971         length <= (juint) value->length()) {
2972       st->print(BULLET"string: ");
2973       java_lang_String::print(obj, st);
2974       st->cr();
2975       if (!WizardMode)  return;  // that is enough
2976     }
2977   }
2978 
2979   st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj));
2980   FieldPrinter print_field(st, obj);
2981   do_nonstatic_fields(&print_field);
2982 
2983   if (this == SystemDictionary::Class_klass()) {
2984     st->print(BULLET"signature: ");
2985     java_lang_Class::print_signature(obj, st);
2986     st->cr();
2987     Klass* mirrored_klass = java_lang_Class::as_Klass(obj);
2988     st->print(BULLET"fake entry for mirror: ");
2989     mirrored_klass->print_value_on_maybe_null(st);
2990     st->cr();
2991     Klass* array_klass = java_lang_Class::array_klass(obj);
2992     st->print(BULLET"fake entry for array: ");
2993     array_klass->print_value_on_maybe_null(st);
2994     st->cr();
2995     st->print_cr(BULLET"fake entry for oop_size: %d", java_lang_Class::oop_size(obj));
2996     st->print_cr(BULLET"fake entry for static_oop_field_count: %d", java_lang_Class::static_oop_field_count(obj));
2997     Klass* real_klass = java_lang_Class::as_Klass(obj);
2998     if (real_klass != NULL && real_klass->is_instance_klass()) {
2999       InstanceKlass::cast(real_klass)->do_local_static_fields(&print_field);
3000     }
3001   } else if (this == SystemDictionary::MethodType_klass()) {
3002     st->print(BULLET"signature: ");
3003     java_lang_invoke_MethodType::print_signature(obj, st);
3004     st->cr();
3005   }
3006 }
3007 
3008 #endif //PRODUCT
3009 
3010 void InstanceKlass::oop_print_value_on(oop obj, outputStream* st) {
3011   st->print("a ");
3012   name()->print_value_on(st);
3013   obj->print_address_on(st);
3014   if (this == SystemDictionary::String_klass()
3015       && java_lang_String::value(obj) != NULL) {
3016     ResourceMark rm;
3017     int len = java_lang_String::length(obj);
3018     int plen = (len < 24 ? len : 12);
3019     char* str = java_lang_String::as_utf8_string(obj, 0, plen);
3020     st->print(" = \"%s\"", str);
3021     if (len > plen)
3022       st->print("...[%d]", len);
3023   } else if (this == SystemDictionary::Class_klass()) {
3024     Klass* k = java_lang_Class::as_Klass(obj);
3025     st->print(" = ");
3026     if (k != NULL) {
3027       k->print_value_on(st);
3028     } else {
3029       const char* tname = type2name(java_lang_Class::primitive_type(obj));
3030       st->print("%s", tname ? tname : "type?");
3031     }
3032   } else if (this == SystemDictionary::MethodType_klass()) {
3033     st->print(" = ");
3034     java_lang_invoke_MethodType::print_signature(obj, st);
3035   } else if (java_lang_boxing_object::is_instance(obj)) {
3036     st->print(" = ");
3037     java_lang_boxing_object::print(obj, st);
3038   } else if (this == SystemDictionary::LambdaForm_klass()) {
3039     oop vmentry = java_lang_invoke_LambdaForm::vmentry(obj);
3040     if (vmentry != NULL) {
3041       st->print(" => ");
3042       vmentry->print_value_on(st);
3043     }
3044   } else if (this == SystemDictionary::MemberName_klass()) {
3045     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(obj);
3046     if (vmtarget != NULL) {
3047       st->print(" = ");
3048       vmtarget->print_value_on(st);
3049     } else {
3050       java_lang_invoke_MemberName::clazz(obj)->print_value_on(st);
3051       st->print(".");
3052       java_lang_invoke_MemberName::name(obj)->print_value_on(st);
3053     }
3054   }
3055 }
3056 
3057 const char* InstanceKlass::internal_name() const {
3058   return external_name();
3059 }
3060 
3061 void InstanceKlass::print_loading_log(LogLevel::type type,
3062                                       ClassLoaderData* loader_data,
3063                                       const char* module_name,
3064                                       const ClassFileStream* cfs) const {
3065   ResourceMark rm;
3066   outputStream* log;
3067 
3068   assert(type == LogLevel::Info || type == LogLevel::Debug, "sanity");
3069 
3070   if (type == LogLevel::Info) {
3071     log = Log(class, load)::info_stream();
3072   } else {
3073     assert(type == LogLevel::Debug,
3074            "print_loading_log supports only Debug and Info levels");
3075     log = Log(class, load)::debug_stream();
3076   }
3077 
3078   // Name and class hierarchy info
3079   log->print("%s", external_name());
3080 
3081   // Source
3082   if (cfs != NULL) {
3083     if (cfs->source() != NULL) {
3084       if (module_name != NULL) {
3085         if (ClassLoader::is_jrt(cfs->source())) {
3086           log->print(" source: jrt:/%s", module_name);
3087         } else {
3088           log->print(" source: %s", cfs->source());
3089         }
3090       } else {
3091         log->print(" source: %s", cfs->source());
3092       }
3093     } else if (loader_data == ClassLoaderData::the_null_class_loader_data()) {
3094       Thread* THREAD = Thread::current();
3095       Klass* caller =
3096             THREAD->is_Java_thread()
3097                 ? ((JavaThread*)THREAD)->security_get_caller_class(1)
3098                 : NULL;
3099       // caller can be NULL, for example, during a JVMTI VM_Init hook
3100       if (caller != NULL) {
3101         log->print(" source: instance of %s", caller->external_name());
3102       } else {
3103         // source is unknown
3104       }
3105     } else {
3106       oop class_loader = loader_data->class_loader();
3107       log->print(" source: %s", class_loader->klass()->external_name());
3108     }
3109   } else {
3110     log->print(" source: shared objects file");
3111   }
3112 
3113   if (type == LogLevel::Debug) {
3114     // Class hierarchy info
3115     log->print(" klass: " INTPTR_FORMAT " super: " INTPTR_FORMAT,
3116                p2i(this),  p2i(superklass()));
3117 
3118     if (local_interfaces() != NULL && local_interfaces()->length() > 0) {
3119       log->print(" interfaces:");
3120       int length = local_interfaces()->length();
3121       for (int i = 0; i < length; i++) {
3122         log->print(" " INTPTR_FORMAT,
3123                    p2i(InstanceKlass::cast(local_interfaces()->at(i))));
3124       }
3125     }
3126 
3127     // Class loader
3128     log->print(" loader: [");
3129     loader_data->print_value_on(log);
3130     log->print("]");
3131 
3132     // Classfile checksum
3133     if (cfs) {
3134       log->print(" bytes: %d checksum: %08x",
3135                  cfs->length(),
3136                  ClassLoader::crc32(0, (const char*)cfs->buffer(),
3137                  cfs->length()));
3138     }
3139   }
3140   log->cr();
3141 }
3142 
3143 #if INCLUDE_SERVICES
3144 // Size Statistics
3145 void InstanceKlass::collect_statistics(KlassSizeStats *sz) const {
3146   Klass::collect_statistics(sz);
3147 
3148   sz->_inst_size  = wordSize * size_helper();
3149   sz->_vtab_bytes = wordSize * vtable_length();
3150   sz->_itab_bytes = wordSize * itable_length();
3151   sz->_nonstatic_oopmap_bytes = wordSize * nonstatic_oop_map_size();
3152 
3153   int n = 0;
3154   n += (sz->_methods_array_bytes         = sz->count_array(methods()));
3155   n += (sz->_method_ordering_bytes       = sz->count_array(method_ordering()));
3156   n += (sz->_local_interfaces_bytes      = sz->count_array(local_interfaces()));
3157   n += (sz->_transitive_interfaces_bytes = sz->count_array(transitive_interfaces()));
3158   n += (sz->_fields_bytes                = sz->count_array(fields()));
3159   n += (sz->_inner_classes_bytes         = sz->count_array(inner_classes()));
3160   sz->_ro_bytes += n;
3161 
3162   const ConstantPool* cp = constants();
3163   if (cp) {
3164     cp->collect_statistics(sz);
3165   }
3166 
3167   const Annotations* anno = annotations();
3168   if (anno) {
3169     anno->collect_statistics(sz);
3170   }
3171 
3172   const Array<Method*>* methods_array = methods();
3173   if (methods()) {
3174     for (int i = 0; i < methods_array->length(); i++) {
3175       Method* method = methods_array->at(i);
3176       if (method) {
3177         sz->_method_count ++;
3178         method->collect_statistics(sz);
3179       }
3180     }
3181   }
3182 }
3183 #endif // INCLUDE_SERVICES
3184 
3185 // Verification
3186 
3187 class VerifyFieldClosure: public OopClosure {
3188  protected:
3189   template <class T> void do_oop_work(T* p) {
3190     oop obj = oopDesc::load_decode_heap_oop(p);
3191     if (!obj->is_oop_or_null()) {
3192       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p2i(p), p2i(obj));
3193       Universe::print_on(tty);
3194       guarantee(false, "boom");
3195     }
3196   }
3197  public:
3198   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }
3199   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
3200 };
3201 
3202 void InstanceKlass::verify_on(outputStream* st) {
3203 #ifndef PRODUCT
3204   // Avoid redundant verifies, this really should be in product.
3205   if (_verify_count == Universe::verify_count()) return;
3206   _verify_count = Universe::verify_count();
3207 #endif
3208 
3209   // Verify Klass
3210   Klass::verify_on(st);
3211 
3212   // Verify that klass is present in ClassLoaderData
3213   guarantee(class_loader_data()->contains_klass(this),
3214             "this class isn't found in class loader data");
3215 
3216   // Verify vtables
3217   if (is_linked()) {
3218     // $$$ This used to be done only for m/s collections.  Doing it
3219     // always seemed a valid generalization.  (DLD -- 6/00)
3220     vtable().verify(st);
3221   }
3222 
3223   // Verify first subklass
3224   if (subklass() != NULL) {
3225     guarantee(subklass()->is_klass(), "should be klass");
3226   }
3227 
3228   // Verify siblings
3229   Klass* super = this->super();
3230   Klass* sib = next_sibling();
3231   if (sib != NULL) {
3232     if (sib == this) {
3233       fatal("subclass points to itself " PTR_FORMAT, p2i(sib));
3234     }
3235 
3236     guarantee(sib->is_klass(), "should be klass");
3237     guarantee(sib->super() == super, "siblings should have same superklass");
3238   }
3239 
3240   // Verify implementor fields
3241   Klass* im = implementor();
3242   if (im != NULL) {
3243     guarantee(is_interface(), "only interfaces should have implementor set");
3244     guarantee(im->is_klass(), "should be klass");
3245     guarantee(!im->is_interface() || im == this,
3246       "implementors cannot be interfaces");
3247   }
3248 
3249   // Verify local interfaces
3250   if (local_interfaces()) {
3251     Array<Klass*>* local_interfaces = this->local_interfaces();
3252     for (int j = 0; j < local_interfaces->length(); j++) {
3253       Klass* e = local_interfaces->at(j);
3254       guarantee(e->is_klass() && e->is_interface(), "invalid local interface");
3255     }
3256   }
3257 
3258   // Verify transitive interfaces
3259   if (transitive_interfaces() != NULL) {
3260     Array<Klass*>* transitive_interfaces = this->transitive_interfaces();
3261     for (int j = 0; j < transitive_interfaces->length(); j++) {
3262       Klass* e = transitive_interfaces->at(j);
3263       guarantee(e->is_klass() && e->is_interface(), "invalid transitive interface");
3264     }
3265   }
3266 
3267   // Verify methods
3268   if (methods() != NULL) {
3269     Array<Method*>* methods = this->methods();
3270     for (int j = 0; j < methods->length(); j++) {
3271       guarantee(methods->at(j)->is_method(), "non-method in methods array");
3272     }
3273     for (int j = 0; j < methods->length() - 1; j++) {
3274       Method* m1 = methods->at(j);
3275       Method* m2 = methods->at(j + 1);
3276       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
3277     }
3278   }
3279 
3280   // Verify method ordering
3281   if (method_ordering() != NULL) {
3282     Array<int>* method_ordering = this->method_ordering();
3283     int length = method_ordering->length();
3284     if (JvmtiExport::can_maintain_original_method_order() ||
3285         ((UseSharedSpaces || DumpSharedSpaces) && length != 0)) {
3286       guarantee(length == methods()->length(), "invalid method ordering length");
3287       jlong sum = 0;
3288       for (int j = 0; j < length; j++) {
3289         int original_index = method_ordering->at(j);
3290         guarantee(original_index >= 0, "invalid method ordering index");
3291         guarantee(original_index < length, "invalid method ordering index");
3292         sum += original_index;
3293       }
3294       // Verify sum of indices 0,1,...,length-1
3295       guarantee(sum == ((jlong)length*(length-1))/2, "invalid method ordering sum");
3296     } else {
3297       guarantee(length == 0, "invalid method ordering length");
3298     }
3299   }
3300 
3301   // Verify default methods
3302   if (default_methods() != NULL) {
3303     Array<Method*>* methods = this->default_methods();
3304     for (int j = 0; j < methods->length(); j++) {
3305       guarantee(methods->at(j)->is_method(), "non-method in methods array");
3306     }
3307     for (int j = 0; j < methods->length() - 1; j++) {
3308       Method* m1 = methods->at(j);
3309       Method* m2 = methods->at(j + 1);
3310       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
3311     }
3312   }
3313 
3314   // Verify JNI static field identifiers
3315   if (jni_ids() != NULL) {
3316     jni_ids()->verify(this);
3317   }
3318 
3319   // Verify other fields
3320   if (array_klasses() != NULL) {
3321     guarantee(array_klasses()->is_klass(), "should be klass");
3322   }
3323   if (constants() != NULL) {
3324     guarantee(constants()->is_constantPool(), "should be constant pool");
3325   }
3326   const Klass* host = host_klass();
3327   if (host != NULL) {
3328     guarantee(host->is_klass(), "should be klass");
3329   }
3330 }
3331 
3332 void InstanceKlass::oop_verify_on(oop obj, outputStream* st) {
3333   Klass::oop_verify_on(obj, st);
3334   VerifyFieldClosure blk;
3335   obj->oop_iterate_no_header(&blk);
3336 }
3337 
3338 
3339 // JNIid class for jfieldIDs only
3340 // Note to reviewers:
3341 // These JNI functions are just moved over to column 1 and not changed
3342 // in the compressed oops workspace.
3343 JNIid::JNIid(Klass* holder, int offset, JNIid* next) {
3344   _holder = holder;
3345   _offset = offset;
3346   _next = next;
3347   debug_only(_is_static_field_id = false;)
3348 }
3349 
3350 
3351 JNIid* JNIid::find(int offset) {
3352   JNIid* current = this;
3353   while (current != NULL) {
3354     if (current->offset() == offset) return current;
3355     current = current->next();
3356   }
3357   return NULL;
3358 }
3359 
3360 void JNIid::deallocate(JNIid* current) {
3361   while (current != NULL) {
3362     JNIid* next = current->next();
3363     delete current;
3364     current = next;
3365   }
3366 }
3367 
3368 
3369 void JNIid::verify(Klass* holder) {
3370   int first_field_offset  = InstanceMirrorKlass::offset_of_static_fields();
3371   int end_field_offset;
3372   end_field_offset = first_field_offset + (InstanceKlass::cast(holder)->static_field_size() * wordSize);
3373 
3374   JNIid* current = this;
3375   while (current != NULL) {
3376     guarantee(current->holder() == holder, "Invalid klass in JNIid");
3377 #ifdef ASSERT
3378     int o = current->offset();
3379     if (current->is_static_field_id()) {
3380       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");
3381     }
3382 #endif
3383     current = current->next();
3384   }
3385 }
3386 
3387 
3388 #ifdef ASSERT
3389 void InstanceKlass::set_init_state(ClassState state) {
3390   bool good_state = is_shared() ? (_init_state <= state)
3391                                                : (_init_state < state);
3392   assert(good_state || state == allocated, "illegal state transition");
3393   _init_state = (u1)state;
3394 }
3395 #endif
3396 
3397 #if INCLUDE_JVMTI
3398 
3399 // RedefineClasses() support for previous versions
3400 
3401 // Globally, there is at least one previous version of a class to walk
3402 // during class unloading, which is saved because old methods in the class
3403 // are still running.   Otherwise the previous version list is cleaned up.
3404 bool InstanceKlass::_has_previous_versions = false;
3405 
3406 // Returns true if there are previous versions of a class for class
3407 // unloading only. Also resets the flag to false. purge_previous_version
3408 // will set the flag to true if there are any left, i.e., if there's any
3409 // work to do for next time. This is to avoid the expensive code cache
3410 // walk in CLDG::do_unloading().
3411 bool InstanceKlass::has_previous_versions_and_reset() {
3412   bool ret = _has_previous_versions;
3413   log_trace(redefine, class, iklass, purge)("Class unloading: has_previous_versions = %s",
3414      ret ? "true" : "false");
3415   _has_previous_versions = false;
3416   return ret;
3417 }
3418 
3419 // Purge previous versions before adding new previous versions of the class and
3420 // during class unloading.
3421 void InstanceKlass::purge_previous_version_list() {
3422   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
3423   assert(has_been_redefined(), "Should only be called for main class");
3424 
3425   // Quick exit.
3426   if (previous_versions() == NULL) {
3427     return;
3428   }
3429 
3430   // This klass has previous versions so see what we can cleanup
3431   // while it is safe to do so.
3432 
3433   int deleted_count = 0;    // leave debugging breadcrumbs
3434   int live_count = 0;
3435   ClassLoaderData* loader_data = class_loader_data();
3436   assert(loader_data != NULL, "should never be null");
3437 
3438   ResourceMark rm;
3439   log_trace(redefine, class, iklass, purge)("%s: previous versions", external_name());
3440 
3441   // previous versions are linked together through the InstanceKlass
3442   InstanceKlass* pv_node = previous_versions();
3443   InstanceKlass* last = this;
3444   int version = 0;
3445 
3446   // check the previous versions list
3447   for (; pv_node != NULL; ) {
3448 
3449     ConstantPool* pvcp = pv_node->constants();
3450     assert(pvcp != NULL, "cp ref was unexpectedly cleared");
3451 
3452     if (!pvcp->on_stack()) {
3453       // If the constant pool isn't on stack, none of the methods
3454       // are executing.  Unlink this previous_version.
3455       // The previous version InstanceKlass is on the ClassLoaderData deallocate list
3456       // so will be deallocated during the next phase of class unloading.
3457       log_trace(redefine, class, iklass, purge)
3458         ("previous version " INTPTR_FORMAT " is dead.", p2i(pv_node));
3459       // For debugging purposes.
3460       pv_node->set_is_scratch_class();
3461       // Unlink from previous version list.
3462       assert(pv_node->class_loader_data() == loader_data, "wrong loader_data");
3463       InstanceKlass* next = pv_node->previous_versions();
3464       pv_node->link_previous_versions(NULL);   // point next to NULL
3465       last->link_previous_versions(next);
3466       // Add to the deallocate list after unlinking
3467       loader_data->add_to_deallocate_list(pv_node);
3468       pv_node = next;
3469       deleted_count++;
3470       version++;
3471       continue;
3472     } else {
3473       log_trace(redefine, class, iklass, purge)("previous version " INTPTR_FORMAT " is alive", p2i(pv_node));
3474       assert(pvcp->pool_holder() != NULL, "Constant pool with no holder");
3475       guarantee (!loader_data->is_unloading(), "unloaded classes can't be on the stack");
3476       live_count++;
3477       // found a previous version for next time we do class unloading
3478       _has_previous_versions = true;
3479     }
3480 
3481     // At least one method is live in this previous version.
3482     // Reset dead EMCP methods not to get breakpoints.
3483     // All methods are deallocated when all of the methods for this class are no
3484     // longer running.
3485     Array<Method*>* method_refs = pv_node->methods();
3486     if (method_refs != NULL) {
3487       log_trace(redefine, class, iklass, purge)("previous methods length=%d", method_refs->length());
3488       for (int j = 0; j < method_refs->length(); j++) {
3489         Method* method = method_refs->at(j);
3490 
3491         if (!method->on_stack()) {
3492           // no breakpoints for non-running methods
3493           if (method->is_running_emcp()) {
3494             method->set_running_emcp(false);
3495           }
3496         } else {
3497           assert (method->is_obsolete() || method->is_running_emcp(),
3498                   "emcp method cannot run after emcp bit is cleared");
3499           log_trace(redefine, class, iklass, purge)
3500             ("purge: %s(%s): prev method @%d in version @%d is alive",
3501              method->name()->as_C_string(), method->signature()->as_C_string(), j, version);
3502         }
3503       }
3504     }
3505     // next previous version
3506     last = pv_node;
3507     pv_node = pv_node->previous_versions();
3508     version++;
3509   }
3510   log_trace(redefine, class, iklass, purge)
3511     ("previous version stats: live=%d, deleted=%d", live_count, deleted_count);
3512 }
3513 
3514 void InstanceKlass::mark_newly_obsolete_methods(Array<Method*>* old_methods,
3515                                                 int emcp_method_count) {
3516   int obsolete_method_count = old_methods->length() - emcp_method_count;
3517 
3518   if (emcp_method_count != 0 && obsolete_method_count != 0 &&
3519       _previous_versions != NULL) {
3520     // We have a mix of obsolete and EMCP methods so we have to
3521     // clear out any matching EMCP method entries the hard way.
3522     int local_count = 0;
3523     for (int i = 0; i < old_methods->length(); i++) {
3524       Method* old_method = old_methods->at(i);
3525       if (old_method->is_obsolete()) {
3526         // only obsolete methods are interesting
3527         Symbol* m_name = old_method->name();
3528         Symbol* m_signature = old_method->signature();
3529 
3530         // previous versions are linked together through the InstanceKlass
3531         int j = 0;
3532         for (InstanceKlass* prev_version = _previous_versions;
3533              prev_version != NULL;
3534              prev_version = prev_version->previous_versions(), j++) {
3535 
3536           Array<Method*>* method_refs = prev_version->methods();
3537           for (int k = 0; k < method_refs->length(); k++) {
3538             Method* method = method_refs->at(k);
3539 
3540             if (!method->is_obsolete() &&
3541                 method->name() == m_name &&
3542                 method->signature() == m_signature) {
3543               // The current RedefineClasses() call has made all EMCP
3544               // versions of this method obsolete so mark it as obsolete
3545               log_trace(redefine, class, iklass, add)
3546                 ("%s(%s): flush obsolete method @%d in version @%d",
3547                  m_name->as_C_string(), m_signature->as_C_string(), k, j);
3548 
3549               method->set_is_obsolete();
3550               break;
3551             }
3552           }
3553 
3554           // The previous loop may not find a matching EMCP method, but
3555           // that doesn't mean that we can optimize and not go any
3556           // further back in the PreviousVersion generations. The EMCP
3557           // method for this generation could have already been made obsolete,
3558           // but there still may be an older EMCP method that has not
3559           // been made obsolete.
3560         }
3561 
3562         if (++local_count >= obsolete_method_count) {
3563           // no more obsolete methods so bail out now
3564           break;
3565         }
3566       }
3567     }
3568   }
3569 }
3570 
3571 // Save the scratch_class as the previous version if any of the methods are running.
3572 // The previous_versions are used to set breakpoints in EMCP methods and they are
3573 // also used to clean MethodData links to redefined methods that are no longer running.
3574 void InstanceKlass::add_previous_version(InstanceKlass* scratch_class,
3575                                          int emcp_method_count) {
3576   assert(Thread::current()->is_VM_thread(),
3577          "only VMThread can add previous versions");
3578 
3579   ResourceMark rm;
3580   log_trace(redefine, class, iklass, add)
3581     ("adding previous version ref for %s, EMCP_cnt=%d", scratch_class->external_name(), emcp_method_count);
3582 
3583   // Clean out old previous versions for this class
3584   purge_previous_version_list();
3585 
3586   // Mark newly obsolete methods in remaining previous versions.  An EMCP method from
3587   // a previous redefinition may be made obsolete by this redefinition.
3588   Array<Method*>* old_methods = scratch_class->methods();
3589   mark_newly_obsolete_methods(old_methods, emcp_method_count);
3590 
3591   // If the constant pool for this previous version of the class
3592   // is not marked as being on the stack, then none of the methods
3593   // in this previous version of the class are on the stack so
3594   // we don't need to add this as a previous version.
3595   ConstantPool* cp_ref = scratch_class->constants();
3596   if (!cp_ref->on_stack()) {
3597     log_trace(redefine, class, iklass, add)("scratch class not added; no methods are running");
3598     // For debugging purposes.
3599     scratch_class->set_is_scratch_class();
3600     scratch_class->class_loader_data()->add_to_deallocate_list(scratch_class);
3601     return;
3602   }
3603 
3604   if (emcp_method_count != 0) {
3605     // At least one method is still running, check for EMCP methods
3606     for (int i = 0; i < old_methods->length(); i++) {
3607       Method* old_method = old_methods->at(i);
3608       if (!old_method->is_obsolete() && old_method->on_stack()) {
3609         // if EMCP method (not obsolete) is on the stack, mark as EMCP so that
3610         // we can add breakpoints for it.
3611 
3612         // We set the method->on_stack bit during safepoints for class redefinition
3613         // and use this bit to set the is_running_emcp bit.
3614         // After the safepoint, the on_stack bit is cleared and the running emcp
3615         // method may exit.   If so, we would set a breakpoint in a method that
3616         // is never reached, but this won't be noticeable to the programmer.
3617         old_method->set_running_emcp(true);
3618         log_trace(redefine, class, iklass, add)
3619           ("EMCP method %s is on_stack " INTPTR_FORMAT, old_method->name_and_sig_as_C_string(), p2i(old_method));
3620       } else if (!old_method->is_obsolete()) {
3621         log_trace(redefine, class, iklass, add)
3622           ("EMCP method %s is NOT on_stack " INTPTR_FORMAT, old_method->name_and_sig_as_C_string(), p2i(old_method));
3623       }
3624     }
3625   }
3626 
3627   // Add previous version if any methods are still running.
3628   // Set has_previous_version flag for processing during class unloading.
3629   _has_previous_versions = true;
3630   log_trace(redefine, class, iklass, add) ("scratch class added; one of its methods is on_stack.");
3631   assert(scratch_class->previous_versions() == NULL, "shouldn't have a previous version");
3632   scratch_class->link_previous_versions(previous_versions());
3633   link_previous_versions(scratch_class);
3634 } // end add_previous_version()
3635 
3636 #endif // INCLUDE_JVMTI
3637 
3638 Method* InstanceKlass::method_with_idnum(int idnum) {
3639   Method* m = NULL;
3640   if (idnum < methods()->length()) {
3641     m = methods()->at(idnum);
3642   }
3643   if (m == NULL || m->method_idnum() != idnum) {
3644     for (int index = 0; index < methods()->length(); ++index) {
3645       m = methods()->at(index);
3646       if (m->method_idnum() == idnum) {
3647         return m;
3648       }
3649     }
3650     // None found, return null for the caller to handle.
3651     return NULL;
3652   }
3653   return m;
3654 }
3655 
3656 
3657 Method* InstanceKlass::method_with_orig_idnum(int idnum) {
3658   if (idnum >= methods()->length()) {
3659     return NULL;
3660   }
3661   Method* m = methods()->at(idnum);
3662   if (m != NULL && m->orig_method_idnum() == idnum) {
3663     return m;
3664   }
3665   // Obsolete method idnum does not match the original idnum
3666   for (int index = 0; index < methods()->length(); ++index) {
3667     m = methods()->at(index);
3668     if (m->orig_method_idnum() == idnum) {
3669       return m;
3670     }
3671   }
3672   // None found, return null for the caller to handle.
3673   return NULL;
3674 }
3675 
3676 
3677 Method* InstanceKlass::method_with_orig_idnum(int idnum, int version) {
3678   InstanceKlass* holder = get_klass_version(version);
3679   if (holder == NULL) {
3680     return NULL; // The version of klass is gone, no method is found
3681   }
3682   Method* method = holder->method_with_orig_idnum(idnum);
3683   return method;
3684 }
3685 
3686 #if INCLUDE_JVMTI
3687 JvmtiCachedClassFileData* InstanceKlass::get_cached_class_file() {
3688   if (MetaspaceShared::is_in_shared_space(_cached_class_file)) {
3689     // Ignore the archived class stream data
3690     return NULL;
3691   } else {
3692     return _cached_class_file;
3693   }
3694 }
3695 
3696 jint InstanceKlass::get_cached_class_file_len() {
3697   return VM_RedefineClasses::get_cached_class_file_len(_cached_class_file);
3698 }
3699 
3700 unsigned char * InstanceKlass::get_cached_class_file_bytes() {
3701   return VM_RedefineClasses::get_cached_class_file_bytes(_cached_class_file);
3702 }
3703 
3704 #if INCLUDE_CDS
3705 JvmtiCachedClassFileData* InstanceKlass::get_archived_class_data() {
3706   assert(this->is_shared(), "class should be shared");
3707   if (MetaspaceShared::is_in_shared_space(_cached_class_file)) {
3708     return _cached_class_file;
3709   } else {
3710     return NULL;
3711   }
3712 }
3713 #endif
3714 #endif